I have an 87 IROC-Z, has the stock L98 350. Originally had a 700r4, I swapped to a T56 using the guide here on this forum. The swap went fine, I changed nothing electrical other than cutting the auto shifter wires and wiring in the clutch pedal and reverse lights. Everything there works as intended. Car ran fine prior to the swap. Would start at the first turn of the key almost always, even if it had sat still for 2-3 weeks without being started. Now, it won't start unless the battery is on a charger (even tho the battery is testing full). Its almost like it needs an extra bit of power to get it going. The engine turns over the way it should, it just won't fire without that extra juice. I re-wired the cigarette lighter, cause it was cut when I bought the car, so I thought maybe it was draining battery and that's what was causing it. Pulled the fuse, and its still doing the same thing. So it obviously wasn't the lighter addition.

I'm using a Perfection Clutch kit from RockAuto, 153 Tooth LT1 flywheel, and a Powermaster PowerMax Plus starter with 11:1 compression ratio for (153-168 tooth). Ignition isn't stock and was installed prior to this transmission swap. But for references, its an MSD Black Widow set up with High Vibration MSD Blaster Coil (PN 8222) and PN 6425 Black MSD 6AL box. Not sure on the distributor, cause I don't have the box it came in.

I'm NOT a mechanic. This swap was my first go around with anything major on a car that wasn't brakes or shocks etc. I did not install the ignition system, I paid a friend of mine to do so last year. I do know, to get power to the fuel injectors, he had to use a sep ignition module in conjuction with the 6AL. I had a friend of mine who knows cars, come over and check things and we found some loose wire connections on the 6AL etc, and fixed those and while he was there, car was firing just fine. 2 days later, it won't start again.

Any ideas?? Maybe it's something simple/stupid that I can fix here without paying someone. I'm about to send it to my mechanic and just let him deal with it, cause it has to go over there anyways again soon cause he's putting digital gauges in it.

 

Huh, that’s a odd spot for a icm without a heat sink.

 

Check you positive and negative connections battery, starter and block. The injectors get power from the fusebox. Through c207 the connector in your picture and out the passenger side kick panel to injectors.
looks like the injectors power has been spliced into.

 

The injectors are getting powered thru that spliced ICM. It was the only way my mechanic could find online when installing an MSD unit on this engine, so thats how we did it. Ive tried 2 diff batteries, they both do the same thing. One is an Optima Red top that i bought new last fall, and i had zero issues with, and had it tested at advanced when this all started, and they sold me a Diehard battery that doesnt even have an hr worth of run time on it and stays fully charged and it does the same thing too. My friend that fixed the wire connections, used his voltage tester on all the connections and everything was good.

So the fuse box wire goes to the connector, then out to the injector? I have no idea how to even begin to check this stuff. This all may seem obvious or easy to alot of you guys on here, but literally I'm learning as I go.

Just doesn't make any sense to me how it was fine til i pull a transmission and touch nothing else besides a starter swap (which is easy and i've done many times b4 in my mechanical past)...Now it wont work lol

 

Don’t you have a different starter since the swap ?
to much amp draw while cranking?

 

Yea I had to swap starters, cause according to the guides I read on here and other posts, that massive automatic starter wouldn't work with the 153 tooth LT1 flywheel. What I read, if I had a 5 speed car prior, which I couldnt have since mines the 5.7, then I could use the same starter with the swap. I actually tried 2 diff 1995 LT1 starters in this ordeal. The donor car I pulled my swap parts from, had 200k miles on it. So i just left the slave/flywheel/clutch and starter on it and bought all new stuff. I originally bought a (PURE ENERGY 6470SN) cheap brand one from Rockauto that was more of a mini style, and ended up buying the Powermaster one I listed in the first post. They both doing the same thing. We've even tried a new 6AL and new coil, same thing.

 

I would be cutting out that MSD box and have things wired properly.

Tuned Performance is right about power connections. I would especially check the Negative cable to make sure it has a good solid connection to the block. I have seen the negative power cable not hooked up on a chevy truck and it turned over like the battery was about the die.

 

See it doesn't act like the battery is dead or lacking crank power. It turns like its about to start and never does. Then if I hook up a battery charger or maintainer...by the time i turn it on and get back to the key it fires right up. Thats all it takes. Its almost like its not getting enough power, but nothing changed with the ignition.

Last friday, I had it to where it would start on key turn with the diehard battery i mentioned above. Let it sit for 24hrs untouched til Sat evening and it fired one turn of the key, let it run for 10-15 mins. Waited another 24 hrs til Sun evening and it fired again one turn of the key and let it run. Didn't touch it again for 24hrs til Monday night it wouldnt start again. I dont get it.....

 

Heres a video of what its doing.

 

What gauge are your battery cables, and how old are they?

 

If it turns over that fast it is either fuel or spark. Have you tried holding the gas pedal to the floor while cranking to see if it fires? I still don't understand why your mechanic butchered the wiring like that. No need for a MSD box to begin with.

 

They are stock gauge I believe and look fairly clean like they been replaced. I bought this car Feb 2019, and I haven't changed them or had a reason to. The neg is grounded on the engine via the alternator bracket.

Yes I have tried holding the gas pedal down, it does the same thing. The MSD set up was my idea. Pricing at the time of this was only a couple hundred more than to replace the stock stuff and I chose this b/c I could reuse it down the road on something else or resell it for decent money. The distributor and ignition went bad last summer and this is what I chose to replace it with. I have ad zero issues with it, til i yanked the 700R4 out. Car would always fire on 1 turn of the key and barely crank over before it started, Even if it had sat for 2 weeks without being started. Now it can't sit more than a day and it wont start again. Thats why I'm confused. It's getting ready to go back to my mechanic here soon, as I talked to him yesterday. I was just curious if there was any ideas on here before I did to try and save a little cash. When the cars over there, I watch and learn what he does and what not so I can do it on my own later. Long process for someone whos never had a project car or built anything engine wise.

 

Any updates?

 

Not currently. I haven't had time to do much with it. Im taking it to a shop here soon and I will update people on this thread on the issues. Maybe itll help someone else down the road if this same issue crops up for them. I appreciate all the replies, I will let everyone know when I know.

 

What about now?

 

Isn't there a bunch of ground wires at the back of a cylinder head? Did you have to disturb these when you did the tranny swap?

 

I'd start buy pulling out everything MSD and putting the ign system back to stock. I've tossed so many msd coils it's not funny.
The last one was on a 70 trans am a few weeks ago. Brand new coil, leaking secondary voltage to primary side. Crazy voltage spikes all over the electrical system.

 

I've tossed two MSD coils. One was DOA the other failed after a short time

 

Yeah the MSD stuff is crap and entirely unnecessary. It won't make a single more HP over stock anyway.

You have a huge rats nest of a mess on your hands. Put the ignition system back to stock and perhaps you have a chance of troubleshooting it if that doesn't cure the problem on its own.

GD

 

No changes, car hasn't moved as of yet.

 

What about now?

 

Nothing has changed. The guy I had lined up to work on, kept making excuses or ignoring my texts so I just gave up on him and called a shop who was supposed to do muscle car upgrades etc. I towed it to their shop and it sat for a month and they didnt even touch it. I called them in advance, told them what I did and what was going on and had a few other things I wanted to do while it was there (coolant leak, reverse lockout install, new aftermarket gauges)....They came back and said "I didnt know it was a project car....so I cant work on it every day or have the time to take away from my normal repair work to get it done....."...like i left the console/panels out so he could access the wiring and save him time....so that was a total waste of my time more or less and I had to go tow it back to my house...im out $160 from 2 Uhaul trailer rentals b/c of it and still not fixed...

My friend, whos a decent mechanic, has been researching on his end and hes supposed to come over this saturday to double check everything and run tests. If he cant figure it out, I have a couple other shops within a 30 mile radius im going to call and see if theyll work on it. Most local places here wont touch it cause its aftermarket so I have to expand my search to a hot rod/custom shop and none are close by here that I know of. Theres an engine builder/dyno but they dont do anything other than building/tuning engines. So still a work in progress...If he cant figure it out, im gonna rip the MSD out and go back to stock. Then maybe a shop around here local will work on it...

It starts just fine if the block is warm. But on a cold start, it wont without being on a charger or jumper cables. I'll post an update after my friend looks at it this weekend.

 

That is a bummer that no one wants to work on it. Too bad we are in different countries. This is a project I would take on for free!

 

I appreciate that, I wish you were too cause I've been slamming my head against a wall for a year now with this deal....but, we may have some good news on this. My buddy came over last night for about 5 hrs and we diagnosed everything just to be 100% sure on all of it. Has good spark. Has good voltage to the injectors with the key off. Has good voltage to the starter. All of the MSD/Ignition components have good voltage with key on and under load. All fuses are good (which I had checked long b4 I even made this post cause im not a total dummy lol). We checked all the battery cables/connections, they were good. We checked all the grounds, they were solid. And sometimes last night when attempting to start, it would randomly start. Which was baffling both of us cause its never done that b4. The times it wouldnt, my buddy was using a power probe volt meter tool, and when trying to crank over and it wasnt, hed press the button on the probe and it would start....which is what it did b4, so we just assumed it was a bad connection somewhere cause a little bit more juice and it would start.

So i pulled out my shop manual, not the chilton/haynes books, the actual shop manual that i got off ebay. He read thru it, finally got to a troubleshooting place with the fuel injection and the problem it was having and the flowchart says if all of this stuff was good, the ECM is faulty/going bad. Which WOULD make total sense, cause when i originally started this swap and i pulled the console out, the previous owner had left a hot wire wide open and it touched bare metal and shot a bunch of fuses (i wasnt aware it existed until it sparked). So i disconnected the battery, and changed fuses and taped up that wire and went on about my business. The fact I changed nothing on my end with the wiring and all the fuses and everything was good, it has to be the ECM. So I ordered a reman'd one off RockAuto and when it gets in, I'll install and update. HOPEFULLY this is the problem, I don't see how it can be anything else and if it is, im glad I didnt pay some shop to do all this and theyd charge me $2000....***Fingers Crossed!!!***

 

I'm rooting for you!

One other thing to check is if you actually have fuel pressure at the fuel rail at the schrader valve. It could be a intermittent fuel pump issue.

 

Yea that is where here checked the fuel pressure. Right there under the vaccum hose back by the distributor on the pass side of the fuel rail. and it was pushing 45lbs

 

Hopefully I didn't miss something. So we know you have 45psi at the rails. Crank the car like in the video. Then pull a spark plug, it should be wet with fuel. Or get a noid light kit from autozone. Hook it up to one of your injectors and crank the car. The noid light should flash. If it does, or your spark plug is wet with fuel. You know your injectors are working, and is most likely a spark issue.

 

Well boys, the new ECM came in today....i swapped out the PROM, plugged it up, hooked the battery back up and she cranked smoother than she has in the 2 years ive had it. I hadn't touched the car all week since my buddy left and normally when this happens, I have to get out the jumper cables. Im going to wait a couple days, try it again but it SEEMS like we figured it out....

 

Hope it's fixed! I had an issue a few years back where the car would randomly stop running. Or sometimes it wouldn't start. I went through EVERYTHING. The last thing I tried was replacing the ECM and that was the problem.

 

well I went to a wedding yesterday and tried to fire it when i got home, and it cranked right over. Got up this morning and piddled around the house, went to fire it and its back to what it was doing...im about over this car...nothing ever works for me lol

 

How have you been making out?

 

I appreciate you checking in. I haven't gotten any further with this after the ECM change. It just frustrated me to all get out. Im contemplating between A) Starting the build/restoration/LS swap process now, or B) Gutting the entire MSD ignition crap and going back to stock and starting from there to see if thats whats causing the problems. I just dont see how it is the MSD stuff, cause b4 I pulled the tranny to do the swap, it was literally fine. I just don't get it...

I recently purchased another 87 IROC thats in better physical condition and has T-Tops, for dirt cheap. this one has a Carbed 383 stroker crate swap and a 5 speed T-5. So I been having a little fun with it instead of thinking about the other one AT ALL. So it's making my decision to just start the restore process on the other easier to do by the day to be honest.

 

Just like the deep mysteries of the universe. I have to have answers on this one.