1967 RS Duramax Camaro

Someone correct me if I'm wrong but the ecu does not need the maf working correctly, at least on the older engines, to start.

Buddy of mine put an aftermarket bigger CP3 on his truck, same thing, would not start, and the truck ran fine before the pump install. Called the pump guy and he said to get it started on ether and sometimes the bigger pump really needs spun harder than the starter will do on the first fire up. We thought he was nuts but we tried it and it worked like a champ. We were really careful with the ether, just short pulses of spray, just barely enough to keep it running for like 10 seconds, and then it just took off on its own and has been fine ever since.

Didn't read through the entire thread to see which pump you are using, so hopefully this is of some help to you.
 
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The MAF does not need to be plugged in. When I worked at the dealership I would have half the engine torn down with no valve cover, only important things plugged in and it would fire. I'm pretty sure the system has to reach 10mpa for the injectors to start injection, I might be off on my numbers, but do you have a seperate lift pump on it?
 
Yes I have a 175gph pusher pump feeding the cp3 through -8 fuel lines. Spraying starting fluid down the y bridge kinda scared me. I would much rather try ether, since it's actually for diesels.

I've gotten a lot of tips and advice from the guys on duramaxdiesels, and I will be making a few phone calls today. I hope to get to the bottom of this soon.
 
Starting fluid = ether. There used to be a brand that didn't hit nearly as hard as the regular stuff but I can't find it anymore. Flammable brake cleaner will work too and it doesn't rattle as bad.

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I have seen the cam and crank sensors not work in one engine but work in another. Did the ones you have come from that engine and are they in the proper positions (cam in the cam, etc)?

Grounds need to be all over the car. ECM needs to have it's on power and ground, frame ground, engine ground, can't have enough grounds.
 
I'd disconnect the glow plugs if you are going to do much starting fluid squirting. MAF doesn't need to be connected. There isn't much that does need to be connected for it to run on a LBZ. Cam, Crank, rail sensor, injector harnesses and IIRC it will fire.

I had a no start issue with my camino. swapped the cam/crank sensors from another engine and it fired right up. The sensors that didn't work, went into anther truck and it fired and is still running.
 
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IdahoRob said:
I have seen the cam and crank sensors not work in one engine but work in another. Did the ones you have come from that engine and are they in the proper positions (cam in the cam, etc)?

Grounds need to be all over the car. ECM needs to have it's on power and ground, frame ground, engine ground, can't have enough grounds.
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I have not taken the cam or crank sensors out since I've had the Duramax. As far as I know, they are in the correct positions.

I have a ground strap going from the block to the chassis, one from the tranny bell housing to the chassis, the battery is grounded directly to the rear chassis, the body of the Camaro is bolted and welded to chassis. I'm going to check all of the grounds, including the ground for the ecm.

IdahoRob said:
I'd disconnect the glow plugs if you are going to do much starting fluid squirting. MAF doesn't need to be connected. There isn't much that does need to be connected for it to run on a LBZ. Cam, Crank, rail sensor, injector harnesses and IIRC it will fire.

I had a no start issue with my camino. swapped the cam/crank sensors from another engine and it fired right up. The sensors that didn't work, went into anther truck and it fired and is still running.
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I'm going to refrain from using the starting fluid. Interesting about the cam and crank sensors in your el camino... I will have to look into that.

slick06 said:
nice ride!!!
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:thankyou2:

chevota84 said:
Will the snap on scanner check rail while its cranking?

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Headcase98002 said:
The Solus pro will, that is what I use.
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I'm going to hook ours up tomorrow and check the rail pressure while cranking.
 
chevota84 said:
Starting fluid = ether. There used to be a brand that didn't hit nearly as hard as the regular stuff but I can't find it anymore. Flammable brake cleaner will work too and it doesn't rattle as bad.

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Now I feel a little more stupid. Been thinking for years that ether was a different kind of starting fluid...:doh:
 
So I learned a few things today: the plugs for the cam and crank sensors are identical, and I had them switched around. Fixed that issue. Talked to Dan at PPE and he instructed me the right way to disable the VATS with their programmer, because I was doing it wrong.

I called Rick and he also gave me good advice on his own experiences with the Chevelle.

It still won't fire on it's own. So... Now I'm coming to these possible conclusions:

Cam and/or crank sensors need to be changed
Re-check the ground for the ecm, possibly all grounds on the whole car again
I need to watch the rail pressure with the shops Solus Pro scanner to see what it's doing while cranking

If you guys have anymore advice, please feel free to chime in.
 
You can use WD-40 instead of either and it will not be as harsh. We have seen worn out injectors cause this problem. There is not enough psi built to start, but once running it will start fine the rest of the day. You may have an air lock in the fuel system.
 
I haven't seen a lot of LB7 Duramax injectors with excessive return rate, but I have seen a lot of them that just leak out the tip like crazy. I alway just pull the glow plugs and crank over, you should see any fuel come out.
 
I'd check rail pressure first.

If that checks out get an injector test noid light and plug into each injector harness and check to see if it lights while cranking. I remembered these from my gasser mechanic days, but they also work on a diesel to see if the injectors are getting a signal. O'Rielly's have a whole kit of them for like $25.00
 
WI Huck said:
You can use WD-40 instead of either and it will not be as harsh. We have seen worn out injectors cause this problem. There is not enough psi built to start, but once running it will start fine the rest of the day. You may have an air lock in the fuel system.
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Never thought about WD-40.

Headcase98002 said:
I haven't seen a lot of LB7 Duramax injectors with excessive return rate, but I have seen a lot of them that just leak out the tip like crazy. I alway just pull the glow plugs and crank over, you should see any fuel come out.
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I was going to have the injectors tested while I was installing the head studs, but my local diesel shop was going to ship them down to southern California and charge me an arm and a leg. I was told this LBZ only had aroung 30k miles when pulled, but I could have been lied to.

IdahoRob said:
I'd check rail pressure first.

If that checks out get an injector test noid light and plug into each injector harness and check to see if it lights while cranking. I remembered these from my gasser mechanic days, but they also work on a diesel to see if the injectors are getting a signal. O'Rielly's have a whole kit of them for like $25.00
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Hooked up our scanner this morning and cranked it over to monitor rail pressure, and it was building up pressure, then the scanner would lose communication for a moment so I had to stop cranking. I need to install a larger cable up to the starter so it doesn't lose so much voltage.

Also, while data scanning I found that neither the cam or crank sensors were giving off any signal. They are both plugged in, so I think this might be the culprit to my problem.
 
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