RFmaster

ZIP your log and post it.

//RF

Cartrax

Thanks. Mine is an Aeromotive also. Putting off further pump tests for a bit. On to the O2 sensor - think I have a spare (crazy things you replace when you have no clue what the issue is). Will continue posting saga...

Cartrax

OK. EDIT: File too large after compression (1.2). Will create shorter log to post. Assume I will get similar results since nothing will be changed - but with this animal ya never know .

Cartrax

Ran for signifacntly shorter time but file size didn't diminish much. Can not get under 1M again. Will have to create another version.

EDIT: Ended up emailing the file. If you are curious, send me a private message with address and I'll email you the data log.

Cartrax

Nothin' like quoting yourself. I found more info on RBob's site - Titled "Embedded Lockers Classic What's Up Display". This what I was looking for.

Cartrax

Just took my grandson for a drive and made it an the opportunity to create another log. This one is really short perfect for an upload. BTW - car still runs like poop.

RFmaster

CarTrax

You need to run some VE learns - based on your last data log ccv_001_17_14 your BLM's are in 108 region - very rich!

Under cruise conditions BPC drops down to 86 (30 to 40 kpA). I'll have to dig into this a bit deeper than originally I've thought.

//RF

RBob

iTrader: (1)

What the master of RF says about doing VE Learns. Plus, while logging hitting the space bar places markers in the data stream. Can use this to mark areas of the log where the engine backfires or some other anomaly.

RBob.

RFmaster

CarTrax

Additional observations from the data log:
1) BPC varies - do you have VRFPR? From the post - Yes - high vacuum 13 in-HG, load 18 in-HG. You've said that you're running with 90 lb-hr injectors.
2) Idle is very rich - run VE learn just at idle. I know you're running a cam, but it is not that big - this one can be tamed.
3) You have plenty of fuel flow - DC under acceleration <60%

4) Start with VE learns at idle and progress onward. Save to new bin, follow with light throttle just above idle. Save to a new file. Gentle steady rate throttle driving. Save to a new bin. Do baby steps first before jumping into throttle issues. Keep notebook - record what you're doing, changes made.

//RF

Cartrax

I noticed that, really surprised since symptoms were indicating a lean condition.

Cartrax

Ok thanks.

Cartrax

Yes VRFPR. OK will do and post. Thanks for your help.

What about the in and out of closed/open loop? An indication of a bad O2? or normal? O2 is heated.

RFmaster

O2 appears to be fully functional since voltage swing from 0.040 to 980 mV

//RF

Cartrax

OK. I should ignore the on/off closed loop green light condition on the WUD during the test drives then?

Cartrax

Advised this was normal - didn't want to go after learns with a potential O2 issue.

Always appreciate input. When you're new at efi tuning it can be overwhelming. In fact if I would have found someone to handle this for me I would have gladly footed the bill - hopefully this will start to become fun soon.

Cartrax

UPDATE - Created a new VE Learn bin at idle from best guess BIN. Test drove with new BIN - seemed to idle better but data log s indicating it's still running rich - yes rich (BLM 108). Backfiring as usual with slight load - no real improvement noticed yet.

I read I could actually create a new VE Learn BIN from a data log so I tried to keep the RPMs around 1300 to 1400 with varying loads during the test drive. I did create a new VE Learn BIN from the data log but I'm having a problem getting the WUD to recognize it as a new BIN. Assume you can do this. I'm going back to try it again.

usc iroc

Been reading through the post and just want to verify something....you said you replaced the Harmonic balancer...If it wasn't an OEM replacement, did you verify that the timing marker was in the exact location as the old one? Have seen where aftermarket balancer wil have different marks and could be throwing your base timing off.

Cartrax

This is what I did - (from an earlier post) "Damper TDC seems on based on sort of an unconventional test I performed a while back. I pulled #1 plug and inserted a wooden dowel into the chamber. Hand cranking the engine I noted the dowel extended the furthest amount out of the chamber at 0°/ supposed highest piston position. Slight hand cranking past TDC either way and the dowel would start to slip back into the chamber."

Made this up no idea if this is a good test or not. If there's another/better way to check it, let me know.

Would love to find something like that to correct.

usc iroc

I am assuming the old motor ran fine, you pulled it, rebuilt the stock motor, and re-installed it. Fired it up and now it backfires.

Cartrax

A lot of mods and unfortunately I can't put my finger on where it exactly started. Old tired plant ran Ok with stock ECM. It's been through a couple of shops. Shop #1 outsourced the rebuild but then gave up waiting on the Renegade and wanted to carb it. I pulled it and shop #2 completed the install with the Renegade, stock injectors and EBL ECM. It ran without backfiring but was hard to start and lacked power. They had no clue how to tune it with the EBL and started over charging me for minor tweaks so I brought it home.
I replaced a number of sensor type components, almost all the vacuum hoses, parallel plumbed it, changed injectors and added Vac referenced FPR. Been playing with for about two years now just getting into the EFI tuning. So long answer and no, I can’t exactly pinpoint where or what mod may have created the backfiring.

Dominic Sorresso

Where are you located?

RFmaster

Renegate intake has a very large plenum which will require extensive AE tweaking. As it stands right now you'll need to go through initial stages of VE learns to get base fuel into shape - where it should be for BLM around 128 counts +/- 3counts. I am going to assume that mechanically your engine is in good shape.
From EFI perspective I would like to see idle VE area dialed in before drawing any further conclusions. So, as I have mentioned previously complete VE learns at idle and light throttle (under 2000 RPM).

//RF

Cartrax

Not real far - Dundee area near Randall and Huntley.

Cartrax

Update -

Great news – on a hunch I pulled the vacuum connection to the VRFPR plugged the lines and test-drove it. No data log cuz I really wasn't expecting much. To my surprise this cured 99% of the backfiring. Only a couple of times when I was canning it did I get pops. Other times ¼, ½, full throttle – no pops. It could have been more responsive but I assume that will come with better tuning. Also got a little feel for this engine’s potential – I think I’m gonna like it.


I’ll be looking into why this fixed things but your comments and suggestions are welcomed.

Cartrax

Thanks much for your help (and everyone's) as soon as I get my arms around this VRFPR issue I'll be following your recommendations. I'll probably continue with posts simply cuz I need the tuning help - probably under a new thread.

RBob

iTrader: (1)

OK, doing that increased the fuel pressure and in turn increased the volume of AE. Didn't we already increase the AE by 25% at one point?

Double it this time, both the "AE - MAP PW" and the "AE - TPS PW" tables. Flash that in and re-connect the vacuum line on the VRFPR.

Need to get it to stop backfiring before VE Learns can be done.

RBob.

RFmaster

Rbob

I have a suspicion that Cartrax 90 lb-Hr injectors are from late model 454! As we all know late model 454 used 46 lb-Hr injectors (rated at 13 PSI) with FPR set for 30 PSI. When you take a look at datalog file I would expect to see idle pulse width for a pair 90 lb-Hr (at 13 PSI) to be very close to 1.1 to 1.2 mSec at idle. Instead, I see 2.2 mSec PW at idle (850 RPM). True 90 lb-Hr (rated at 13 PSI) do not need that much pulse at idle, with FP around 13 PSI!!!

CarTrax
Can you please post injector part number etched on the top of injector. It should be visible with connector removed.

//RF

Cartrax

Actually 50%, which is where they are now. I also played with another 50% on the map (essentially doubling the ebl base) did not notice any improvement. It certainly appears to be a fuel pressure issue.

Cartrax

GM5235231*RPD

RFmaster

Injectors are right for the job ->5235231 - Red / Blue - 80pph (@13PSI) - 7.4L / 454 - 88-90

Cartrax

So, they're two 80's? I need to re-do the BPC calc then from to 90 to 80. Then keep jacking the AE and duration until I get rid of the backfiring?

Think I'm going to check the FP stability again with the vacuum hose off the VRFPR b4 I do anything.

RFmaster

Yes, keep bumping AE until popping goes away. But I'm also curious if one of the two injectors is flowing less than advised.

BPC vs. vacuum table (18 PSI with vacuum port unplugged) for 80 lb-Hr injectors
VAC BPC
0 90
5 91
10 93
15 96
20 98
25 100
30 103
35 106
40 109
45 112
50 116
55 120
60 125
65 130
70 136
75 142
80 150

usc iroc

Sounds good Cartrax.....ready to se some 1/4mile times....lol

I enjoy the community of this site. The way everyone will help another figure out and tune their project is awesome.

Cartrax

Can I test/observe potential issue? or Do I need to send "em out for flow testing?

RFmaster

One way to determine if the two injectors are about the same is to perform 'a crude balance test'. On 220 TBI it is easy to perform - I am not sure if it can be done on CFI due to two single TB's spaced apart on intake manifold.
Basically, fire up engine let it warm-up to normal operating temperature and idle in CL. In WUD observe BLM.
Disconnect one injector - observe BLMs climb. Note BLM value. Engine should still be able to idle on a single injector. Reconnect injector plug and let BLM values return back to steady state idle values previously observed. Perform the same disconnect with the other injector. For nearly identical injectors the BLM increase should be the same. Intake manifold distribution will have some effect on fuel distribution and idle quality.

Otherwise, tearing TB fuel pods apart and sending injectors for flow testing is the only way to determine if they are the same (and their actual flow rate). After years of playing around with EFI I only install flow tested injectors. This removes a layer of uncertainty.

//RF

Ronny

iTrader: (1)

Has fuel pressure yet been monitored (by passanger)with a gauge taped to windshield under heavy load?

My 80 lb injectors at 21 lbs FP flow a ton of fuel. My values in TPS and MAP AE are at low of 122 then incrementally up to 427. Then with 50-80% removed incrementally from 2200 rpms-5000 rpms with RPM modifier.

Cartrax

FP's stable. Needle movement under load with full throttle almost unnoticeable.

Cartrax

Yep, just did it again see last post. Thanks for the numbers, I'll compare to where I am.

Where is your VRFPR vacuum line attached? Mine's on the back of the passenger side TBI. First port on right looking from inside the car. Could I be getting bad readings there?

RFmaster

I would put a vacuum gauge on that port to be sure! It should be a full time vacuum port unaffected by throttle plate position. Try to use PB vacuum port with T.

//RF

Cartrax

Engine struggled then killed with one TBI. Tried both.

Cartrax

These the comparable tables? My values are much different if I selected the correct info. These are with the 50% recommended increase.

Edit - Ronny,

As I recall, you have a different manifold. Maybe the Renegade just requires a ton of AE.

Anyone tuned in running the Renegade? Comments/experience? Thanks.

Cartrax

OK, I pulled the 80's and installed a set of 75's I had flow tested a while back (they match). Had "em installed initially but one wasn't working, this time I crimped the contacts a bit - did the trick. Set the FP to 25 (target ~ 400hp). I'll be checking the vacuum on that TBI port comparing it to the brake vacuum port if same I'm leaving it there. If all goes right I'll tweak the BIN and take it out.

I noticed the 75's have a better looking flow pattern then the 80's - could be from higher FP but cone is wider and looks more atomized? - think that's the correct word. TBIs were pitch black with carbon from backfiring - cleaned "em up.

Will post results...

Oh yeah - Part number GM17084304*RPD. Noticed some rate these as 80's some as 75's both at 13psi. Same noise the the 80's some rate "em as 90's, anyway I'm going to assume they're 75's for the BPC.

Ronny

iTrader: (1)

I am using Holley Projection maniford(dual plane). Soon to be for sale as I am swapping to port fuel with World Products(Accel uses?) SPmanifold and a universal 4B TB.

Cartrax

Test Drive 75#er's, VRFPR Hooked to vacuum source, and latest BIN (Tweaked by RFMaster) - Yes Virginia, there is a Santa Clause! No backfiring under any conditions! Did I say no backfiring? You bet I did!

Thinking those 80#'s were hosed up or maybe the BIN just got tweaked enough - either case we are on to VE learns. Backfiring problem solved!

Thanks for the help folks! Will be moving to another thread with some sort of a tuning title gladly leaving this one....


Might also have been the contacts to the injectors intermittently losing contact - take your pick...

Or maybe the higher fuel pressure is what the Renegade needs - still it's regulated and there was no popping at any time under varying loads.

thomas1976

Good to know you got the backfiring fixed and wow what great help from the awesome tgo members. Sounds like it's time to play with the tune now.

Cartrax

I definitely picked the right place

Cartrax

Hi folks, bit of an update - working with one of your gurus and we're getting the tune under control but we're not there yet. Need a WBO2 to finesse it more, next planned mod...

Real reason for this post - I'm looking for a decent set of plugs to put in. Cleaned the the old ones but they were really carboned up. I need shorties cuz of the headers. What do you guys recommend?

Can't think of a better place to ask, thanks.

Cartrax

Update - Sounded like the car developed a nasty knock, so I socked some coin away and brought the car into a reputable shop. Good news/Bad news - Noise source was an exhaust leak./They found engine was out of balance - caused bearing wear, crank run, and leaky seals. Block needs machining, so for a bit more I'm having "em convert it to a 383 Stroker. Will need a base bin if anyone can recommend one - would be appreciated. I'm having the shop dyno tune it from there.

Ronny

iTrader: (1)

Just need to change the BPC(see utility) for 383 CID...May need the crank and choke values addressed if it setting insufficient fuel.