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I converted my '90 S-10 to a MPI 350, and repined it to a 7730 ECM.
The motor is fresh, I just rebuilt it a year or so ago. It had no injectors, when I bought the MPI setup, and I bought what was suppose to be good pull outs, for a 350. Now 15yrs later, I put it all together.
My problem is it runs rich, smoking rich! How do I know if I have the right injectors, or if the fuel reg is working right.
I'm kinda starting all over on what's, what, and what does what. How do I know if it's the ecm, injectors, reg, or something else I'm missing right now.
Any help would be good. I have forgotten so much about electronic injection, it's not funny!
Injector body number ? They look like Delphi or multecs 24#hr. Does fuel pressure rapidly drop after prime ? Any fuel in for vacuum hose ? CT’s reading properly?
what’s the tune based off of aujp ?
The numbers on the left side are ---> 17090154 & 2740KFZ
I have the same year '91 Camaro 305 with MPI, and it has the grey injectors. I was "told" that the 350 used the black ones. Now that might be a bunch of BS, or true. I don't know. When I bought this setup (MPI) it came from a '91 305 also. I was then told just to get the black ones for my 350.
"Does the fuel pressure rapidly drop after prime"
I'll have to get a fuel gauge for it. mine is just for carb's, low pressure.
When I was first trying to get it to run, it seemed like it was only running on the prime. and ran crappy for the few seconds it would run. I pulled the dist and replaced the ign modual, cap & rotor with brass contacts. Then got it to run, but was really rich
"Any fuel in the vacuum lines"
I don't think there is, but I'll check them.
"CT's reading properly" I don't know what you asking. Sorry.
"What's the tune based off of aujp"
I don't know what your asking. You had burned my chip for me some 3yrs or so ago. Ya, I know a long time ago! I have been taking care of my Very Ill wife, full time, money was tight because of it, and other things. And my best friend just died suddenly, and just before that, he asked me to get it done. So that light the fire under my butt!
Maybe my S-10 is just Pissed at me, that I gave it a Camaro heartbeat! And a Getrag 5spd. LOL
The numbers on the left side are ---> 17090154 & 2740KFZ
I have the same year '91 Camaro 305 with MPI, and it has the grey injectors. I was "told" that the 350 used the black ones. Now that might be a bunch of BS, or true. I don't know. When I bought this setup (MPI) it came from a '91 305 also. I was then told just to get the black ones for my 350.
"Does the fuel pressure rapidly drop after prime"
I'll have to get a fuel gauge for it. mine is just for carb's, low pressure.
When I was first trying to get it to run, it seemed like it was only running on the prime. and ran crappy for the few seconds it would run. I pulled the dist and replaced the ign modual, cap & rotor with brass contacts. Then got it to run, but was really rich
"Any fuel in the vacuum lines"
I don't think there is, but I'll check them.
"CT's reading properly" I don't know what you asking. Sorry.
"What's the tune based off of aujp"
I don't know what your asking. You had burned my chip for me some 3yrs or so ago. Ya, I know a long time ago! I have been taking care of my Very Ill wife, full time, money was tight because of it, and other things. And my best friend just died suddenly, and just before that, he asked me to get it done. So that light the fire under my butt!
Maybe my S-10 is just Pissed at me, that I gave it a Camaro heartbeat! And a Getrag 5spd. LOL
Thanks, Pat
id look at the body of the injector for any sort of part number. If you said you had a speed density tpi 350 i probably marked the memcal aujp and used that tune deleted vats ect or slightly modified Vette based tuns for manual. Unfortunately i dont recall. The ecm will adjust fueling off inputs one is cts . Coolant temperature sensor. If that is bad reading low the ecm dumps fuel. Do you happen to have a scanner or datalog cable ? To ohm the injectors unplug them and use a volt ohm meter on ohms. Better to do hot but even cold you can test the coils. 15-16.5 really shouldn’t see much more that .5 difference between injectors. Holley even makes a injector that looks like yours but they are bigger than 22#hr.
I checked and used a mirror to see behind. No number or any markings that I could find.
Yes, it's Speed Density.
When I say it runs, it only runs for less then a minute, it runs to rich to idle, almost idled one time, but died. It won't clear out, if I give it more gas. It's hard to start, it cranks alot before it starts. I have no coolant in it yet either. I wanted to fire it up, and get it running first, and let the gaskets seal.
I do have a scanner, other then checking codes, I have not used it.
I will check the injector ohm's tomorrow if it's not raining. Suppose to, I have it outside. I mowed all day today, and half done! Arrr I need a goat! or 10. lol
Everyone is looking at this as a fuel delivery problem, and it very well may be.
I noticed you mentioned vehicle sat a long time and engine is "fresh", but hard to start. How did you set your initial timing?
Everyone is looking at this as a fuel delivery problem, and it very well may be.
I noticed you mentioned vehicle sat a long time and engine is "fresh", but hard to start. How did you set your initial timing?
It sat 3-4yrs? since I assembled it.It sat on a engine stand.I just installed it a couple months ago.
I brought #1 to dtc, then I installed the timing pointer on tdc. Then I installed the dist. I put it about where it should be. I then moved it small amount till it started. I have not had it running long enough to put a light on it to see, or set it right. Plus, it's hard to see the timing marks. (see picture) I was fitting the upper hose.
I do everything old school. When it comes to ecu's, I'm kinda lost, when it comes to trouble
shooting a computer run car.
It's a rainy day, so I won't be working on it today.
Might make sure your basics are covered before you try to diagnose.
set base timing with est disconnected 6-8 dbtdc. After you fill radiator with coolant.
I will fill it. I have had it in & out many times clearing the motor pulleys.I found that the bottom pulley was off my 4.3, and was 1/4" or so shorter, and walked the belt to the back. Picture is before I cleared them again, and I now made a better rad top cover. I will now fill it. I'm done with pulling the radiator.
I have the pointer set at 6 dbtdc. I will set the timing once I get it to idle/run.
I am building a 327 with 2x4 tunnel, zoomie exhaust right now for my Coupe. That's the type engines I built growing up. I ran 1/4 mile & street racing. It's when I work with injection that confuses me.
I think, figuring out, not what does what, but more what causes what, and what to change to fix it, that gets me.
I have been trying to figure out what has been causing my Blazer to miss fire at idle, and a occasional hick-up while driving. I put my meter on it and always said 301 I think, for a year or more.I finally change the 3rd brass cap & rotor, plugs to a different heat range (because I had them), and wires. It has Never ran as good as it does now! LOL, it still gets the same gas mileage as before. Go figure.
If you were reading the meter, you'd figured it out.
04-27-2024, 07:10 PM
