Hi,
im at my wits end, was hoping for some help.
what I have is a S-10 that I have personally swapped in a TPI 350 from a 86 Camaro. I did this swap 18 years ago. It’s a weekend toy but has had 15-20k miles out on it (35k on the long block.). Truck ran great and was super reliable for the past 18 years until now. (Used a brand new fuel injection connection wiring harness with the swap.)
A few months ago, jumped into it to go somewhere (was at home and sitting for 2 weeks) it fired right up and ran for about 15 seconds and died as if I shut the key off, cranked it and no start, it didn’t even try to catch. So I assumed it was a bad module since I have had them fail in the past.. so I deceided to not diagnose it and put in a new module .. what I ended up doing was installing a brand new Davis United Igntjion (DUI) , it was complete until( 50k coil, ignition module, cap rotor, etc..complete)
it would try to start after I got it installed, but wouldn’t fire. So I then took the msd box off and still no luck. I have 12:volts at the coil. Some times it will fire or try to fire and sometimes it just cranks. One morning it fired right up and ran great in the driveway for 15 minutes, I set the base timing at 6btdc with the ect disconnected. Shut it off, disconnected the battery and plugged back in the etc. Still with a warm engine, it wouldn’t start back up. Tried spraying carb cleaner in the intake and it still didn’t start.
ohmed the fuel injectors, they ohmed bad, so I put 8 new Bosch injectors in it and new fuel pressure regulator, along with both ect sensors. Still won’t fire.. sometimes it sputters and tries to run but won’t stay running, one time I had it to the floor and it would run for 4 minutes at 400rpm with the pedal to the floor. I am at a loss, I literally replaced everything but the fuel pump. (Walbro intank pump with 10k miles on it). I thought maybe the 9th injector was flooding it , so I bought a delete Kit and sent the prom to Harris tuning to delete the injector and use the 8 to cold start inrich
here’s what I replaced since this issue,

COMPLETE DISTRIBUTOR ASSY WITH MODULE, COIL CAP ROTOR
FUEL PRESSURE REGULATOR
BOTH INTAKE ECT SENSORS
SWAPPED MASS AIR FLOW SENSORS
8 new FUEL INJECTORS Bosch 4 hole
NEW ECM
SENT THE PROM OUT TO DELETE THE 9th INJECTOR
TPS SET AT .54
Fuel filter
new plugs and spark plug wires,
NEW IGNITION SWITCH
new OIL PRESSURE SWITCH

carb spray doesn’t seem to have a affect on it starting, so I don’t think I have a fuel volume issue. It shows 50psi while cranking
lit has spark, has injector pulse, 12 volts to the injectors, swapped fuel pump relay,

truck has no cats so it’s not a plugged exhaust, and truck ran excellent before it was parked. No Egr valve either. No codes in the ecm either. NO VATS in the system.
Battery is a year old and shows 12.36 volts and I checked the grounds on the back of the heads.

thank you for your help. Could some how the fuel pump not be putting out enough volume, but enough pressure? The carb cleaner in the intake does help at all so I don’t think it’s fuel. I pulled the plugs out and they don’t seem to be wet, but I can smell fuel, just not drenched in fuel. Again, the engine is super healthy and ran great before parked.

I also have one of those highway breakdown portable hei ignition boxes , i hooked that up to eliminate the ignition and still shows the same results. It cranks and cranks and sometimes attempts to run but won’t catch.

the aftermarket wiring harness has two hook ups, one key on and crank 12volt and one constant 12 volts, I made sure it has 12 volt in crank and run position as well
Thank you

 

Have you checked the oil pressure switch?

 

Also kind of hard to tell what you truly have, since 86 Camaro's didn't have TPI originally.

 

Actually, 1985 Camaros had TPI available as an option. So did 1986. However, both of those years only had a 305 TPI available.

 

Lol, in my head i was writing 350 tpi, not just tpi, i know very well they had tpi in 86 since i have one in the garage, oops.

 

MAF could be wrong for the car, I've heard they're picky. What Bosch injectors are they? They might not be playing nice with your tune. Since the distributor was out, double check firing order and position of rotor at #1 TDC.

 

yes, it’s brand new

 

what are you talking about? Starting in 85 they had Tuned Port Injectjon. I know what I have

 

I understand they didn’t have 350 tpi in 1986, it’s a 350 with 86 Tpi, I couldn’t have been more clear about that. This is not something that I just slapped together, it’s been in my truck running great for 18 years after I did the swap.

 

I swapped MAFs with two other ones, I sent the chip out to get retuned and mentioned the injectors. The timing is dead on, I had it running for 20 minutes and it ran great and I set the timing.

 

I rechecked this morning, I have injector pulse on both banks, 12volts at the coil, I have spark, fuel pressure is at 50 cranking, it sputters like it wants to start but won’t fire.
Sprayed carb cleaner In the intake, doesn’t change anything so it’s not a fuel delivery issue. Acts like it’s firing order is out, it is not, I checked it 4 times, and like I said, when I did get it running, I set the timing. Yes I disconnected the tan wire to set timing.
plugs are not wet.

my scan tool is not showing cranking rpm, but that doesn’t make sense since it has constant spark. I have a complete new distributor from DUI , that’s module and all. They are a American company, they built it for me prior to shipping it, it’s not Chinese junk.
tired Another good used ECM and same results.
All the pins look good and the harness looks brand new (has maybe 10k miles on entire harness.

this truck is about to get LS swapped if I didn’t already put $600 into fixing this.

 

IAC valve maybe? Or, as mentioned before, oil pressure switch? If the switch doesn’t sense oil pressure it will prevent the engine from starting.

 

the IAC Valve only has to do with keeping a idle, the engine won’t fire up. And again........I Replaced the oil pressure switch... the fuel pump is running i and have fuel pressure the whole time. Spraying Starting fluid in the intake had No affect on it, that would eliminate the switch being the problem

 

Unless you did some creative rewiring and/or eliminated the fuel pump relay for the transplant, the oil pressure switch would have no effect on whether it runs. You've tried manual application of fuel, which would seem to rule out fuel delivery. Do you have a spark tester? The symptoms seem to be pointing toward a weak ignition.

 

I was going to say, do you know for sure you’re getting spark to the plugs?

 

The harness is a stand alone harness, that is not altered at all. Yes, I have a tester and Yes it has spark.

 

Specifically what Bosch injectors are in the car? I'm suspicious of the timing being off, I'd be tempted to physically verify that #1 is at TDC and the rotor is in the correct location.

 

Bosch Gen 3 4 hole injectors. AGAIN... I had it running and set the timing already(yes I disconnected the twn computer distributor wire and set timing at 6 BTDC. When it was running, it ran for 15-20 min in my driveway and ran great. Shut it down, reconnected the wire, disconnected the battery. Went inside for 20 minutess, came back out, wouldn’t resart..so the engine being hot or cold doesn’t matter in the no start issue. I already double checked TDC ON 1.
This was already said in my original post.

 

It's not fuel related, it's not the oil pressure switch, it's not the injectors, the IAC, all that other incidental stuff, you'd get a cough or a rough start or something,

I've had this problem before (several times) where the car runs fine, then nothing and then sort of run and as crazy as it sounds it's a spark problem. And you'll be ready to suck start a pistol trying to figure it out. Even if it worked 5 minutes ago, it's the nature of these cars and something is failing in the ignition. So despite it being a DUI unit I'd bet it's either a pickup coil or a module that's weak or intermittent or just crapped out.

 

Sorry, I see it's not a third gen but its still that style of GM electronics which are sensitive and prone to failure. Try swapping in a known and good distributor, See if that works.

Good Luck

 

I read your original post. Bosch makes a lot of injectors, and given that none of them are direct factory replacements for a TPI system, I was trying to confirm you at least got close with the right lb/hr. Basically, you can't have proper fueling, proper spark, proper timing, and no start. Therefore, I would suggest a fact that you believe to be true about something you have done is not accurate. Or, you've got something else entirely going on in an unrelated area; my engine wasn't starting for a bit and it turned out a bunch of grimy insulation was shorting the wires in my fusebox.

 

UPDATE—SOLVED

let me start by thanking everyone who tried to help me. What a nightmare. Let me also say, that just because you replaced a new part with a new part, it’s not always good. I was fighting a problem, I had compression, I had fuel, I had some spark, but the spark wasn’t a blue spark. Long story short, my brand spanking new Davis United Igniton D.U.I complete(they come complete , module, cap rotor, and coil) (I swapped a coil from my other car, so I know the coil was not at fault) distributor was the problem, I thought maybe their dyna mod ignition control module was bad, so I bought a brand new GM module and still same results. Frustrated and annoyed with this distributor, I ripped it out and sent it back to JEGS. I then decided to order a reman ACDelco unit and this time, I also decided to switch from the large in coil cap to the small distributor cap with external coil. Got my my Acdelco reman distributor installed it, Wired it all up, and then went to start it and still no start, this time it’s wouldn’t even attempt to start. Checked and found now no spark at all.... put in a used ignition control module it it fired up and came to life! It’s annoying that when you buy a reman Acdelco unit, they give you a used ignition control module, but after reading reviews,that’s what they do. So to sum it up, I was right in my very first diannosis, that my ICM was the problem, but since I put all new parts in, I figured, that that’s not it. The $45 part, cost me almost $1000 in parts. I’m beyond annnoyed with DUI Products, and they may be a usa company, they are now probably using China overseas parts, so this will be the last time I buy a DUI part. I hope this will help someone out in the future , if really had me stumped and ready to throw in the towel... I even went up and beyond and removed the 20 gallon gas tank, siphoned out the 20 gallons of fuel and put in fresh gas, thinking it was the problem, and even though I had a fairly new fuel pump, I replaced it with another new walbro since I had the tank out . What a night mare, but now the truck runs like a rocket ship. If this helps atleast one person out there, it’s worth the time to write this post. Thanks again

 

Thank you for the update, and for the priceless reminder that "new" and "remanufactured" parts aren't always "right."

 

For sure fixed and runs absolutely 110%!!

 

Very cool truck. I used to have a 91 blazer that i swapped a 350 into, so i am partial to these trucks

 

Thanks! Very fun to drive. It was my first car. Owned this since 1998