elesone

My friend has a street rod with an 87 L98 which was converted to SD running 7730. When cold his car takes about 3-5 secs of cranking, then starts the moment the key is released to "Run". After running for about 30 seconds, shut it off, it will start almost immediately and never has an issue for the rest of the day. When the car sits over night in the garage (approx. 65*F), the process is repeated. When running it runs great, good throttle response city or highway.
He asked me if I can look at it. I do not know which bin file it has, possibly a stock AUJP. It has the same number of lines as my LB9 305 bin file but different values. The name of the bin is 350novats.bin using $8D. I'm a beginner at this and learning as I go. The experience I have so far is taking my own stock bin and removed VATS and burn a new chip using moates equipment. Can anyone suggest what I can check?

Thank you in advance.

eseibel67

Does the fuel pump prime for 2 seconds when the ignition is turned on before starting?

elesone

Thanks for the reply.
Yes, he even tried priming it 3x by cycling on/off before starting. Same result. I'm thinking fuel pressure regulator. The car has 250 miles on it and everything is brand new or rebuilt. But he does not think the fpr was touched when the motor was rebuilt. The other area I suspect is the oil pressure sensor. Could it be that the system waits for the pressure build up before it activates the injector circuit? If that comes into the picture, I can fool it by jumping the two leads. Right or wrong?

vetteoz

iTrader: (13)

No
Pump only runs for 2 sec to prime the fuel rails,key on.
Engine should start on this pressure ,
OP switch comes online only as a backup to the pump relay should it fail and has no connection to the injectors.
Highly likely the system is not holding the prime pressure ( faulty reg or check valve in tank ) and you are waiting for the OP switch to re-pressurize the rail so it will fire up

elesone

Thanks vetteoz - Where is this check valve located in the tank? Built in the pump itself?

89RAG

I HAD THE SAME PROBLEM WITH MY 305 TPI. CHANGED THE INJECTORS TO FORD MOTORSPORTS AND HAVEN'T HAD THE ISSUE SINCE... IM GUESSING A LEAKY INJECTOR OR 2...

Dirt Monkey

bringing this one back since no result or outcome was posted. I have been having the same issue as the OP. exact same scenario. This is on a swap, all sensors (except the coolant temp)are brand new. New South Bay injectors. It runs great minus the excessive cranking on first start. The fuel regulator is old but tested good. Everything I know tells me that the seat valve in the pump is not holding, but shouldn't a couple key cycles isolate that as the issue. cycling key doesn't seem to help. Any thoughts?

elesone

You are right about the outcome, which is no resolution yet. This have been bugging me because I attempt to close all my issues. What I suspect is possibly related to the ignition switch. There are circuits live on "crank" like the starter solenoid and ignition, where others are NOT. Similarly the solenoid is not in the "Run". My guess is, the switch travels too far or not enough to catch the ignition circuit. Remember this is a hot rod with new wiring and as most hot rods, wiring short cuts are taken. And because the car is in storage, it will not see the road till May. When the nice weather gets here the last thing us hot rod owners want to do is work on them. It ran good, but he tells me that if something needs to tie the car up long enough to work on the ignition switch he will advise me.
This ignition switch theory is only my opinion and not necessarily the cure.
Later.

83HOZ

I'm not a "tuner," but a simple observation that comes to mind is that 1987 used a Cold Start("ninth") injector, whereas 1989 and the 1990-1992 SD years did not. Was this taken into consideration when programming the custom PROM?

darbysan

When I eliminated the 9th injector, I also changed the Crank Fuel PW Modifier vs Ref Pulses to start at 3, rather than 9 in the programming. I thought it was too long.

elesone

As mentioned in post #1 the system was converted to 7730 SD without the 9th injector, $8D and AUJP.

Dirt Monkey

This is interesting. When I did my swap, I did all the mechanical mods/fab but purchased a harness and ECM from Larry's Electric http://larryselectricsite.com/ I plugged the 9th inj and the tune was setup accordingly. But I don't really know how they have it set up. I have not really got that involved into the tuning side. I dont know the difference between $32b, 6E or $8D. The parameter you reduced makes total sense though. Is this something I could change with a laptop, cable and downloadable software? or is it more involved? I think I need to have someone take a look at my tune data.

elesone, I dont want to hijack this, so I will probably start a thread on the tuning side over in that forum. One thing is sure I believe both of our problems are deeper than the usual obvious stuff.