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!

Thanks, Pat

 

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 ?

 

Might hook up an LED to a couple of the injectors to insure they are actually pulsing and not going full open?

 

I suggest you check your injectors, verify the ohms. I had a similar problem on my TPI conversion. My injectors were toast.

Fred

 

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

 

I will pickup a couple of those injector lights
Thanks.

 

I will have to ask how to check them? Just check across the injector plugin contacts? What should the ohms be?

Thanks.

 

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?

 

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.

Thanks!!! Pat

 

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.

Thanks!

 

I still working on it, in between everything else I have to do. I take care of my very ill wife. It's a nurses 24-7 job without the pay! lol But she comes first on everything we do!!!

Since last post I have replaced the plug wires ( used 10.5mm wires, I need all the heat protection I can get on #5&6) , I moved the dist one tooth. It then started up, but still runs to rich to idle. I can't set the time by myself, I need someone to keep it running for me. But! No ****, all my friends & my best friend have died (most from covid), and my neighbor is staying out of town with cancer in his tongue. So, until another guy, an older guy I know, can come over to give me a hand, I'm stuck. I've moved the timing around, and right where it is, it starts right up, and some what runs the best for now, just rich. The motor is stock It was suppose to be from a '91 vette (lmao) and put into a '91 Chevy tank of a station wagon. Son runs it off road, puts a fence post threw oil pan, lightly kills a bearing getting out of field. I got the motor, and rebuilt everything. It was in great shape, I used the cam, it had no wear marks at all on it, and it mic'd out perfect, so I reused it, and also the lifters, but I rebuilt each one. When I got it, it had throttle body on it.

Question! I don't know but would the injectors be giving me the rich, & smoke. Is it from sticky injectors? I also didn't go threw the throttle body it's self, just new gaskets on it. I don't know that much about mpi, but I do a bit around tbi. I can usually look down thew throat, and see how the injectors are flowing, here I can't, but I can either get myself in trouble, or fix a problem. And since this is a custom build, I'm lost as to where to look for problems. As to whether it's a ecu, injector, or ? problem.

And yes, I have the radiator back in again, and filled. and power steering pump seal leak fixed, and clutch slave power bled, and tail pipes on. 2 1/4" all the way with a "X" and out behind the rear tires.

I will be on it again when I get help to time it. But I for some reason keep thinking it's sticking injectors. They have sat a long time since last used by someone else! Aww! I hate that, that just means more money to find out!

Thanks, Pat

 

I have decided it was a fuel problem, thinking that since the injectors are used, and sat. I figured that some might be dirty not sealing shut. So I pulled them. I looked them over, there is zero makings on them! They look just like the oem ones when I see pictures of used ones. I thought of sending them off to be rebuilt, but that's basically the same cost. $25-30 each, plus more if they need more. Plus shipping each way.

So i looked at new, rebuilt Rochester & Bosch were $200, new starts at $50 to $600.
So I bought a injector pulser, cleaner, filters, and correct O-rings. I checked each, and they all checked the same 12.6 ohms. I removed the filters, and gave them a check spray with a black back ground, and they didn't look bad! I though for sure, I'd have a couple leaks, but none! I soaked them in cleaner for a few hours, and then gave them each a pulse test against a black back round to see good, and they all look great to me.

So I installed the new filters & O-rings. I checked the inside of the pressure reg, thinking it could be dirty. It was clean. It's all back together, and runs the same! Over rich, and blue smoke. I have to get it timed yet, almost got it to idle, but not yet!

Well, I got clean injectors!

 

Is it possible the injectors you have are larger than 22-24 lb/hr?

Fred

 

I do Not know anything about the injectors other then their clean! LMAO No really I don't know. I bought them as to being stock chevy 350 MPI injectors, some 17-18years ago, and then sat in a box, till now. There is Zero ID of any kind on them other then they look just like my 305 MPI injectors I have. These are black (I was told to be 350 injectors), 305 gray.

That's all I know. I don't know what lbs they are.
I don't know how to tell what they are.

But it runs rich.
I can't time it with a light yet, It takes 2, when it won't idle, to time it. Until I can get that set correctly, I can't rule anything out. There's no ign, or valve popping of any kind. But I can't rule out that timing is in the ball park yet either. Yet

Thanks, Pat

 

Well, It's been a bad summer for me, my wife has had 2 strokes, in & out of the hospital, I had to help her learn to walk again, and I have to take care of her now.
Doesn't leave me much time for now, to trouble thinking things, and now the motor in our Blazer is down for the count! Blew both head gaskets going up the mountain, blew a 6" crack in the radiator tank. So now there's that now also.

It didn't want to fire up, and run, so I moved the timing a tooth, and it starts better, but still won't run long enough to time it with a light, by myself. I removed the plugs, except #6, I have to drop the header to get it out. They are black from running rich. But also have some white on them. #7 is kind of clean.

Here is a picture of them. As looking at them, left to right #8, #4, #2, #1, #3, #5, #7.
I tried to get better pictures, but my camara works when It wants to, and it doesn't want to right now! Again!

I'm thinking it's the chip, no matter what I do, it doesn't change the way it runs. It will only run 30-45 seconds at best.

Any ideas as to what to do?

Thanks, Pat

 

I’d be glad to read the chip and look at the file installed . But the overfueling sounds like it’s caused by something else. Btw does this have a stock or aftermarket camshaft.

 

TCoupe, I pray that your wife recovers from her stroke. I know what you are going thru.

In the first picture you posted, you show the DS of the engine. I see that you have the PCV hooked to the vacuum line from the brake booster via a "T" fitting then going into the vacuum fitting between the #3 & #5 runners. There is a large vacuum fitting on the DS rear on the plenum, behind the #7 runner. Do you have anything hooked up there or is it plugged? I have my brake booster hooked to the vacuum line behind #7 runner on the plenum. I believe that is the correct routing on an F-body. If that fitting is open, you have a large vacuum leak and the motor may not want to idle.

Fred

 

I Thank You! It's a full time job, But She comes before Anything else! She's my right hand in everything I do.

You know??? I just found the fitting your talking about. But I knew I had it, but it got lost in the hook-up time Duh! It should run then. But I don't think it's going to help the richness, from what I've known, is it should be worse. But I'll go out & fix it, and then put the plugs back in, and give it a go again.

Thanks!
Pat

 

Thanks, But I just found a major vacuum leak. I'm going to put it all back together again, and see how it runs then.

I'm not sure it's the problem, I don't know much if anything about burning or stock chips, so don't think I'm saying any wrong with it. First I have to fix the leak, then hope it's the running problem.

It has a stock cam that supposed to be for a '91 Corvette That's the motor I bought, but it was in my neighbor's '91 Chevy wagon. They put the TPI from the wagon on it. But I tore it 100% apart, and rebuilt everything with new, except the cam. It mic-ed out perfect. No wear. I 100% rebuilt the roller lifters, and their back in the same hole, they came from. Ya I Know, all motor's came in some year Vette! LOL. Along with my '66 327 lol But it did, I bought it in the car, ready to pull.

I'll get it running, and get back with how it's running

Thanks, Pat

 

Sorry it took so long to get ack, I just got my PC back again!

Of course, My truck went down for the weekend! My cat plugged Friday afternoon, and by the time I got it off, ( Had to tac it, and then remove the crossover to weld it. Arrr. I found out I was out of gas on my welded! I'm never out. So, I had to dig out my stick welder and remember how to stick weld again! Good thing I have 3/32 rods. lol I got it, but it's not pretty at one end.

One thing I forgot to say before is, that when I pulled the plugs, the cylinders were giving off a strong gas smell. I put it all back together and had a guy stop by and help me. The best we could get was a short 10-15 second rich runs. He pulled the dipstick out and there's gas in the oil, enough to have to change it. It's flooding the motor.

The only thing I can thing it is, is the ecu/chip. I have checked everything else out, as being good. It's getting to much fuel somehow. I've Opened up and checked the fuel regulator, and it looks good.

Anyone have any other idea's to check out?

Thanks, Pat

 

What could be flooding this out? I've checked everything out. Everything looks good, and checks out good Why is it flooding out, that it won't let it run more than a minute, or so? What would have if I plugged in a different ECM, with a stock chip? Should it not run? What is different, to make it run in a '91 S-10?

I need to get this thing running!

Thanks, Pat