I put a TPI setup on my 55 Chevy about 2003 and it was doing fine up until I put it in storage more or less for a couple years. When I was able to get back to it, I had one problem after another which were no surprise until now.
On a cold start it's clearly flooded badly. I have to hold the accelerator pretty much to the floor to get it running and hold the RPM up at about 2,500 or so for about 45 to 60 seconds for it to clear up. After it warms up for a couple minutes it will idle but has a slight quiver for another couple minutes and then it idles smooth. If I restart within about an hour or so it's okay. But if it cools down completely it's the same routine.
When I decided to wake it up, I replaced the fuel pump and fuel filter.
After this started, I replaced the plugs because of the flooding issue. It started fine the first time and I thought it was just the old fuel that was the problem. I drained it and refilled and added injector cleaner.
Since then I have replaced the injectors, IAC and TPS.
Can and do ECM's die?
Thanks

 

Datalog to confirm sensors aren't whacked. Is it throwing any codes?

 

Jumping out the ALDL doesn't show any codes. I'm pretty ignorant on testing. My son-in-law who just passed away was a very good drivability man. I always went to him for scanning etc. But I no longer have that asset.
I've only put about 1,500 miles on this car since I built it. At that time, I replaced the cap, rotor, wires and module.

This is a warm start: https://www.youtube.com/shorts/rZkrJfxXYUs
This is a cold start: https://www.youtube.com/shorts/3cYZ-X_uKvc

I should have mention I replaced the fuel pressure regulator when this all started.

 

Going to replace the ECM since I can't figure anything else out. Wish me luck.

 

Everything on the engine is purdy much stock and should run on a stock tune, correct???

Which ECM are you using...gonna assume that with SD you're using a 1227730 or underhood 1227727 not that it matters just curious seeing that your profile states the engine came from an '87 Corvette which originally would be a MAF.

Anyhoo...no codes meaning not even the 12???

Can't really tell in your video how much your feathering the pedal. On all my EFI cars, I never touch the pedal during start. In your case knowing that you suspect a flooding condition...over +2.4v on the TPS enables clear flood mode which would cut out the injectors. I'd do WOT starts over feathering the pedal to see if that improves the starting situation.

During open loop starting, the coolant temp sensor probably has the biggest influence. I'd do a resistance check against this chart...


Ability to scan the data on the ECM would be very helpful...more air through the throttle blades may help a rich condition especially if the IAC is maxed out and loses ability to control air flow.

You have nice shiny paint...grounds don't like painted surfaces...

Here's some items that are influenced by the CTS...keep in mind that some of these are only added during crank. I would've posted down below but I wanted to keep the C to F chart near by so you don't need calculate it.

 

Guess I could have given a little more information, sorry.
The engine came from an 87 Vette and is stock. When I was installing it, I switched over to SD so as to do away with the MAF. I am running a stock 127730 ECM and had a fellow I know in Utah take the chip and remove VATS. He went ahead and removed the rev limiter, although I didn't ask or care. I will never take it that high anyway. This is just a cruiser.
The cold start video is after I managed to get it started. I do WOT to start it cold and back off some after it fires. If I don't do WOT it just floods even worse. After it runs long enough to clear out (45 to 60 seconds) it runs fine. I can shut it off and if I restart within an hour or so, I can just reach thru the window and turn the key and it starts and sounds fine.
When I did check for codes, it does flash 12 3 times and if I wait a couple more seconds it flashes 12 again 3 times.

I'm intrigued about the CTS. I will definitely check that.

Thanks

 

If you’re doing wide open throttle starts, your fpr is leaking or injectors are leaking.
I didn’t see mention of fuel pressure after pump prime .

 

Both are new. I originally thought I had an injector or two leaking down and flooding it. So, I replace them as a set. I double check the FPR to be sure it wasn't sending fuel into the plenum.

Pressure is about 37 PSI with the key on only.

 

Well, ECM made no difference. I would really like to keep the TPI, but this is getting pretty frustrating. I called a fellow I know who does diagnostics and he said he no longer had OBD1 equipment and didn't know anyone who did.

 

I still think unmetered fuel is finding its way into the plenum...after the 2 second prime, does it hold at 37 psi (should be more like 43 psi) or does it drop off rapidly???

Out of curiosity since originally an '87 TPI, is any of the cold start still attached to the fuel rail or was a delete kit installed??? Keep in mind this circuit is only energized during crank and if none of the wires are there, well you know...

 

I'd be looking into a failed coolant temp sensor on front of intake

 

On start-up, ecm will fire the injectors with a pre determined routine based on Coolant Temperature (CT). If Your sensor has failed and is sending a -40DegF to the ECM, it will flood the engine. Also, in warm-up stage, in open loop, the CT signal is used to meter fuel. That would explain why it gets better once warmed-up. With failed CT, the ecm should stay in OL.
Be nice to have a datastream

 

Hey ​​​​@Tuned Performance, wouldn't that result in engine running bad all the time? OP stated it stabilizes after engine warm.
Thanks

 

9th injector was deleted. I also used Camaro runners for two reasons, 1. smoother finish and I was going to buff and 2. they eliminate the 9th injector at the intake.

I ordered an CTS and I'll see where that takes me.

Thanks for all the advice.

 

New CTS, no change. I'm beginning to think ignition?

That will be my next thing to check. Everything was new 1,100 miles ago, but what to h*ll.

 

Just covering the basis here. Where was the "CTS" you changed, located?

 

Below the throttle body.

 

Good. Right one!

 

You need a datastream! You would be able to see the CTS and other signals.

Before throwing more parts at it, do a basic spark test on start-up using an inline spark tester.

Have you checked engine ground at back of heads?

 

useless post

 

Old 06-30-2023, 08:15 PM
#10
@stew'86MCSS396
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Join Date: Sep 2002
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Car: '86MCSS
Engine: 396 .030"
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Re: SD setup floodingQuote:
Originally Posted by MikeKy
Both are new. I originally thought I had an injector or two leaking down and flooding it. So, I replace them as a set. I double check the FPR to be sure it wasn't sending fuel into the plenum.

Pressure is about 37 PSI with the key on only.
I still think unmetered fuel is finding its way into the plenum...after the 2 second prime, does it hold at 37 psi (should be more like 43 psi) or does it drop off rapidly???

Out of curiosity since originally an '87 TPI, is any of the cold start still attached to the fuel rail or was a delete kit installed??? Keep in mind this circuit is only energized during crank and if none of the wires are there, well you know...


Fuel pressure drops off rapidly. Like a couple seconds.

 

Rechecked fuel pressure.Key on engine off. Started at 42 lbs and after 60 seconds or so it dropped to 20 lbs.

 

Just to summarize: so far I have replaced the FPR, iac, tps, full set of injectors, ignition module, rotor button, distributor cap and ECM.

 

Well, I finally figured it must be an ignition issue. I replaced the distributor, and it fires right up and idles nicely. BUT, if I start to accelerate, it falls flat and dies. If I play with the pedal, I can get to run above 3,000 RPM.

I sure could use some advice, please.