The_AntiPirate

Ok so when I bought this car a few months ago I knew nothing about TPI at all, I'm learning as a go here and have been lurking here for a while. The car had been sitting for 4 years with overheating problems and burned coolant, fixed the overheating and it ran ok but had less power than it should have, idled a hair high, and would stumble a bit from a dead stop. After sorting out the transmission, wiring, and floor pan replacement I've moved on to the engine and TPI. My god I've made a terrible mistake.

First thing I did was change the IAC, this helped the idle a bit but wasn't much of a difference. It would idle great on a cold start but after driving for a while it would surge into the 2000's when placed in park and then slowly come back down to 1000 or so. So I started checking injectors and fuel pressure, changing sensors that I found corroded or that I thought might be bad. It was running a little rich so I was chasing that issue as well.

As of today I have replaced the following parts,

TPS (twice) set at .54
IAC
CTS
Manifold temp sensor plug had fallen out, reconnected it.
Cap/rotor/plugs/wires/coil
Ignition/timing control module (the one in the dizzy)
A few leaky vacuum hoses, made no difference, no more leaks found with starting fluid
Fuel Pressure Regulator
ECM
MAF sensor
MAF pwr relay
MAF burnoff relay
O2 sensor
EGR
PVC valve
Set timing to 6*btdc, it was 4* retarded
Cleaned the throttle body
All injectors OHM'd at 17 warm
Unplugged 9th injector, no change

Replacing the FPR actually made my fuel pressure and leakdown worse. Before it would hold 40 all the time and wouldn't leakdown at all after the key was off, new FPR is at 38 and dips to 35 running, sometimes lower under throttle, leakdown to 0 in about 2 minutes max, but didn't affect how the car was behaving at all. I was absolutely convinced it was the O2 sensor, but replacing it yielded the exact same result as everything else.

What will happen is, I'll go though and replace some parts, check everything, make sure everything is connected and adjusted properly, then start the car. It will stumble a bit immediately after firing then idle normally for about 10 seconds before revving up on it's own to 2700 and staying there. Literally nothing has changed this. It started after I replaced the TPS the first time due to it having a dead spot. As of now the car is idling at 2700. It has great throttle response and doesn't stumble at all until it warms up, after which it floods itself out if given any throttle at all. The exhaust burns your eyes if you get within 10 feet of the pipes. I'm completely out ideas as to what the heck is going on here.

Checked and rechecked IAC and TPS adjustment over and over, so far I've found that it makes no difference where I set the idle stop screw, it changes absolutely nothing when I hook everything back up. I've tried it with the screw removed completely. I can set the screw with the IAC disconnected and the car in drive, make sure it's at 450rpm, as soon as I plug it back in and start the car it idles just right then slowly increases right back up revving it's brains out. I've even tried backing out the idle screw with the car running, bringing it down to the range it should be in, as soon as I turn the car off and restart it it shoots right back up like nothing has changed.

The_AntiPirate

Vague update, I removed the cat because I thought maybe it's plugged up. No change again. Still not convinced is isn't the O2 sensor even though I just put a brand new denso in it. Correct me if I'm wrong but the car runs in open-loop until it warms up, then switches over to closed-loop? It idles fine until it warms up then revs up and floods, so the issue is only manifesting itself in closed-loop, I would think that points to the O2 sensor since that's the only difference between the two.

Ordered a set of bosch IIIs from southbay since they were on my list of things to change anyway.

IROCgiraffe

iTrader: (3)

Sounds like you have tackled all the obvious. From my reading here as well, I wouldn't be surprised if your fuel pump is slowly acting up. May want to replace it. If it hasn't been replaced than it probably should be.

The_AntiPirate

Well I got the injectors from southbay today, holy crap their shipping is fast. Going to try those out and see if there is any change in the engine's moodiness. Failing that I have headgaskets to do and an intake gasket kit so I'll tear it apart and check for vacuum leaks as well as exhaust leaks anywhere near the O2 sensor.

I didn't even consider the fuel pump since it seems to prime and run fine. Would it be causing the engine to not be getting enough so the ECM is trying to overcorrect and run rich? I haven't changed the fuel pump relay yet if that has any significance.

The_AntiPirate

Might have found the problem. Started pulling apart the top end of the motor on my way down to the headgaskets. Figured I'd check for vacuum leaks and test the injectors while I was at it. Boy was this a big ball of laughs, whoever was working on this before me keeps looking worse and worse as I go along and find hack-job awful repairs.

Mr. Brilliant decided a massive amount of blue RTV was a good substitute for the intake to cylinder head gasket. This did a fantastic job of blowing out around the EGR crossover and creating not only an exhaust leak and a vacuum leak but also dumping exhaust into the #2 and 3 intake runners. Out of all the intake bolts only 4 were tight, the rest could be removed with a nut-driver and almost no effort. Good job there. Head gasket on the passenger was blow out and both had so much gunk clogging the coolant passageways that they were restricted to like 1/4" hole to flow through. Exhaust manifolds just had no gaskets or anything whatsoever, just metal to metal straight to the head.

Injectors were in garbage shape too, glad I'm changing them out for the bosh 3s. They were caked in carbon ( along with everything else) and one of them disintegrated on the way out and left half of itself still stuck in the intake. Fun.

DRIVE2FAST

9 OUT OF 10 TIMES ITS FASTER AND LESS HEADACHE TO START OVER / RUN NEW WIRES ETC.. COMPARED TO TRYING TO DIAG SOME HACK WORK.

Guest

WoW....

kurtis72

I feel your pain brother. The guy who worked on your car must have learned from someone who worked on my 91. They broke EVERY plastic connector to sensors on the top of the motor. I figure they did it on purpose, nobody could be that incompetent...

The_AntiPirate

It really was a mess. That's why I ended up just rebuilding the top end of the motor. Throttle body, plenum, and intake runners had an insane amount of carbon buildup in them, to the point where throttle body cleaner was just running out black and still not making a visible difference. I dropped off the intake manifold assembly along with the heads at my engine shop to get cleaned up, shaved, 3-angle and new stem seals while it's there.

Went through and replaced all the weatherpak connectors that were broken. You're right too kurtis, it feels like with all this sillyness no one could be this incompetent or oblivious but some people man...

pete0013

At least they left your wiring, they cut ( I'm not joking) every wire in my z for the quest to take out the tuned port 350, and swap in a carbed truck motor!! They ruined a lot, including the computer controlled torque convertor lock-up, thanks for costing me $2000.

The_AntiPirate

Well, as drive2fast said, it's better to start over. Not necessarily and I'm now convinced my car is possessed by witchcraft.

Pulled the motor and went through the whole thing, got the heads and intake back nice and clean, installed the new injectors and went through the fuel rail with new O-rings. I did the TB coolant bypass while I was at it, replaced all vacuum hoses, PCV, crankcase breather. I found the EGR solenoid was garbage and had actually partially disintegrated so I replaced that as well, intake air temp sensor, replaced some bad pigtails, new plug wires. TL;DR everything is new now.

Set the timing to 6*BTDC, set the IAC, set the TPS. What does it do?
Exactly the same thing, idling stupid high, floods out, no power, blows smoke. I played around a bit, and bringing the timing back to 0* solves the idle problem and it will idle normally and smoothly. However it now has trouble starting, stumbles/runs poorly for about 15 seconds, and will die if you don't give it a little pedal. It still bogs under WOT from a dead stop, but doesn't flood out like it was doing before, though while driving the kickdown and throttle response are good.

AutoRoc

iTrader: (1)

Is it possible you have a 85-87 base on an 88+ headed engine or vice versa? They have different intake/head angles and you can't mix the vintages. Ie you cant put an 85 intake base on a 89 block/heads.

Or maybe you have a bad cam? Maybe it as a flat tappet cam and the lobes are trashed? Oil look like its full of metal?

I gave in when mine became a nightmare and carb'd mine....It went from running perfect as a 99% stock car to not idling right, hard start, etc replaced everything.. it was still fun and ran 12.80 with some nitrous...haha

The_AntiPirate

Cam is a hydraulic roller, I pulled each lifter out while I was going through and checked all the lobes. Looked good, no signs of excess wear or heat. Oil was clean.

As for the heads/intake, I have no idea. It's possible since the guy I got it from didn't even know that the timing set he was planning to put on was not for this engine, or that the new set of pushrods he had were the wrong length, good thing I checked the part numbers. Is there a date code on the intake/heads somewhere?

APACHE JOHN

huh? outside of the inner 4 bolt holes being a different angle.....well scan that car any codes? might try a different ECM so hard to fix something without seing it. Don't give up you've came to far. What did the PO say did he have big problems?

MrPackstin

iTrader: (9)

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jjcuff1

I am having same issue on my old car that sat forever. I haven't done much other then TPS adjustment fluids and new fuel pump, fuel tank and cleared lines. It cranks over cold easy and idles normal but builds up as it warms to 1000 then have to kick it down. I have not driven it much so not sure of drivability. I am going to do all the things you mentioned above about the sensors just for complete tune up but I suspect our problems might be similar. I do have autoprom so I am scanning as she runs.

My car wont go into closed loop. I am reading that unless the o2 crosses .5v it wont. Even though temps are fine. My MAF is reading high at idle I have to check the ground circuit to see if getting 5v and 12v from relays. If it is then could be ignition coil.

Now it sounds like you replaced all those items above. To be safe I would do the code 33, 34 and code 42 diagnostics check. Assuming your new sensors are all good. the diagnostics then leads you to the ECM grounds and possibly the ECM being bad.

Now your scan would help alot to verify all of the above are now working. SO lets assume they are ( and I hope to be in same situation tonight)

My scans show me that car is reading lean from the sensors and hence closing off the IAC and dumping fuel. but it is rich, so wtf right? In my garage the car runs so rich you will pass out if you run her too long.

So it sounds like we have same problems, I have more probably, lol. So again for your ride assuming (but still check) all the sensors systems are working and voltages right you are still way rich but most likely your car is reading lean. Excess fuel reads lean to the o2 just like air. Also your carbon build up shows that you are rich.

so two areas to check
Check the ECM using the diagnostics, make sure your chip is fully seated, double check grounds, run the code 42,33 diagnostics.

Next, you mentioned you pulled your cat? I did as well, straight pipe from PO. But my AIR systems is still installed and open tubes. I am thinking that my AIR diverter is jacked up to stuck. Think about it. if the divert valve is stuck open to manifolds your system will read lean all then time since you are injecting air. also if it is stuck, and you have not capped off the o2 tube your essentially opening up an exhaust leak since the exhaust will blow by AND the ECM will add 100mv to the o2 readings to account so your are a double wammy your lean condition to the ECM and it then pumps more fuel.

3: If not AIR leak or ECM then last choice is possible injector leak or stuck but they are new, or massive manifold leak as well but again sounds like you nailed all those.

The_AntiPirate

We were brainstorming about it at work today, the thought came up that it might be the timing is screwed up since it has trouble starting, stumbles from idle but revs fine while rolling, and this whole mess starting when I changed the ICM and set the timing.

So I threw my light on and started playing around. The timing holds dead on 6* with the EST disconnected. Reconnect the EST and it jumps to 12* and flutters around by 2* or so while idling. When given throttle, the timing will retard at first, enough to where I can no longer see the mark, and then come back up and advance. I also noticed that intermittently when increasing the throttle slowly, the advance will stop well before it should and go no further even though the throttle has at least half way to go before WOT.

The dizzy itself was pretty corroded inside when I took it apart, I changed the cap/rotor/ICM and cleaned it up. It could be that the dizzy is just taking a dump, it has a good amount of play in the rotor.

AIR system is gone completely. The car has hooker super comps and Y-pipe that is connected with a straight pipe to a hooker cat back. Volt meter I'm using is one of the yellow digital volt meters that walmart sells. Etek something or other, I'm going to replace the distributor while I'm at work tomorrow and I'll use our shop multimeter to set the TPS since I know that's accurate.

The_AntiPirate

OK FANTASTIC, so we swapped the distributer at the shop today and that eliminated 90% of the problem. The whole pickup coil on the old dizzy could be rotated back and forth a little along with being extremely corroded inside. It still has a slight hesitation like the timing is slightly off, I'll need to screw around with it. It's running significantly better and not stumbling and falling on it's *** if I touch the pedal more than a hair. It's just a little slow to pick it's pants up.

I noticed one thing though with my timing light on it. I set the base timing to 6*BTDC but with the EST plugged back in the timing mark is advanced at idle, sitting at about 12o'clock so it's significantly advanced. Is it possible that I'm off by a tooth on the drive gear?

eseibel67

There's really no such thing as being off by a tooth, because the realation of the distributor body to the rotor is all that matters, and the body can be rotated around a lot (several gear teeth either way). So if you set it at 6* advanced with the EST disconnected, you are good. And yes, the computer advances the timing significantly even at idle.

jjcuff1

Dumb question: looking from top down at the timing mark standing over radiator
Which way is advanced? The big V point is facing the driver seat is 0 right and mine is alsmots 2 marks to the left in the 2 valley that is about 5 degrees advance right?

The_AntiPirate

Standing over the radiator looking down, advanced is to your left.

Ok, I installed the rotor pointing almost exactly to a contact so that I would have the most rotation I could get out of the dizzy, wired that contact as #1 with the engine at top dead center on the first cylinder.

Problem is, I understand that it should be advanced some by the EST at idle, but the engine is pinging noticeably so I think I may need to dial back the base timing. When I first got the car it was running 4* ATDC with the EST disconnected. It might be possible that the outer balancer ring slipped a bit since I noticed the rubber looked a little pulled at one spot while I had it off.

jjcuff1

Any the factory settings of 6degrees is atdv or btdc? With my est removed it is 5atdc to te left of zero. So you and both should be the opposite in est mode?

The_AntiPirate

It's supposed to be set BTDC, left of the zero is BTDC

The_AntiPirate

Managed to pull codes from it by wiring up my own check engine light with jumper wires, it's storing a code 42 and a code 33.

EDIT: Code 42 eliminated itself by clearing it and it did not log again, probably set when I changed the distributor and had the EST bypass unplugged.

I started checking into the code 33. I found that I could start the car and then disconnect the MAF with the engine running, and it would cause no change at all. Not even a blip in the RPMs, instant red flag.

Followed the diagnostic check for the Code 33 and found 12v at the D terminal on the MAF connector. It remains 12v hot even with the burnoff relay unplugged, according to the service manual this indicates a short in the wire but I do not believe this to be the case. I noted that this was hot even with the key off so I started searching the wiring schematics, looks like the dark blue wire that feeds terminal D at the MAF sensor is also spliced off of the battery side of the MAF power relay. Disconnecting the MAF power relay also eliminated the voltage at the dark blue wire to terminal D. I suspect the power relay is bad or possibly has been switched with the burnoff relay as they are internally different. I'll play around some more.

hydrolic144

iTrader: (2)

42 will be set when you unplug the EST to do the timing so wouldn't worry about that one. 33 is a MAF code. Seems simple it's the MAF sensor but doing a little search it's usually everything but that and then some. My MAF actually broke on the inside but was kinda hard to see. Had to put it up to light and look through the screen.

The_AntiPirate

IT WAS THE RELAYS, I'll say that for sure after I clear the code and take it for a drive. I started looking at the wires and noticed that one connector has 5 wires and the other has 4, but they can plug in the same way. So I checked the schematic and sure enough the burnoff harness was plugged in to the power relay and the power harness to the burnoff relay.

Swapped them around and no more voltage at the D terminal for the MAF. Like I said though we'll know for sure after a quick drive.

hydrolic144

iTrader: (2)

Right on. Let us know how that drive was!

The_AntiPirate

Well alright then, significantly better! The idle has improved and seems to be stable now, I was able to set the IAC and the TPS correctly and it actually stayed that way without starting to get erratic. It's no longer idling up to 2k in closed loop and holds right where it's supposed to be. Engine startup improved as well after I got the IAC and TPS set, went from having to crank over 6-8 times to maybe 3 or so. I took it for probably a half hour cruise around and there are no stored codes from the ECM so it seems to be happy.

Unfortunately it's still having a throttle response issue when accelerating from idle, though it's completely different from what it was before. The engine would stumble and sound like it was falling on it's face before. The best way I can describe it would be, I can mash the pedal to the floor and it'll accelerate like a honda accord for the first couple seconds, then sort of "catch up" and run like a raped ape. It cannot break the tires free save for a little chirp if I floor it around a 90* corner. When I was pulling back into the garage it sputtered when I shifted into reverse with the wheel locked to the left, I couldn't force it to do it a second time though.

EDIT: I should add that it revs up just fine and responds almost immediately to WOT when sitting in neutral

jjcuff1

what part numbers you use for the relays? I bought a 5 pin relay at advanced today but that was power relay. They did not have burn off in their system. Wonder if I can use 5 pin both spots.

IROCgiraffe

iTrader: (3)

Don't rule out a slowly failing fuel pump.

The_AntiPirate

I wouldn't, mine were switched differently. If you check the MAF relay thread the guy pulled apart a power relay and a burnoff relay and they clearly have different resistors. He said it's possible to use the burnoff relay and the fuel pump relay interchangeably.

I used ACDELCO Part # 212305 (burnoff) and ACDELCO Part # 212300 (power)

I'll check pressure at the rail.

The_AntiPirate

Ok I checked the fuel pressure. At key on, it primes to 42psi and holds there, running it hovers at 38 and will jump to 45 when bumping the throttle.

I did notice that the second time I connected the gauge, there was 0psi at the rail and the car did not prime the fuel pump. I cycled the key on and off a couple times and it did not prime, I had to crank the engine to get pressure at the rail. Failing fuel pump relay?

VincentZ28

iTrader: (2)

Try changing the fuel filter first. If that doesn't work then fuel pump.
When setting the timing, Disconnect the EST, set to *6. Turn the car off, reconnect the EST and you're done. If you check the timing again with the EST connected it should be a 12 O' Clock. This is normal.

The_AntiPirate

I have changed the fuel filter. I'll change the pump and the relay (only relay I didn't replace) anyway just for the heck of it but I went and played with the timing again. I know it should be 6* initial with the EST off but I didn't take into consideration that I raised compression by having the heads and deck shaved when I rebuilt the motor, I'm also running it on 93 octane so I have a slower burn. Just to see what would happen I bumped the initial timing up from 6* to 8* and the car is much more responsive. Not where I want it to be yet but it doesn't accelerate like a honda now. It does have 2.73 rear gears so there's only so much I think I'll be able to get out of it.

I haven't ruled out the transmission being part of this as well since all I've done to the old 700R4 under there is change the fluid and filter after the car had been sitting for 4 years, who knows the last time it was gone through. If the trans is an issue then I'm just ditching the auto and swapping in a 5 speed, even at work I never deal with autos (I work on semi trucks so mostly eaton 10 speeds) so my understanding of them is pretty shade tree.

Bob88GTA

iTrader: (2)

Unbelievable.......funny........but not funny. PO probably rides a tricycle.