Another won't start. EGR question.
02-10-2008, 12:14 PM
#1
Another won't start. EGR question. Painless is closed today so I thought I'd check here for my answer. I'm sure it will be more reliable than their's anyway.
My engine is a '01 and my PCM is a '98. I double checked all of my connections and my only wiring issue is that I do not have a EGR system so I can't plug in the Painless supplied connector. I've read where EGR can be deleted in the PCM but should the engine start if my donor PCM has it programmed in? I don't have the equipment to check the PCM I was going to get it tuned once I get it cranked.
I saw where someone mentioned a difference in the cam shaft positioning sensors on the later model engines. Is this true and would it keep the engine from starting? My harness connector plugged right in so I don't know if I need to pull the starter to check the sensor part #.
I do have good (55psi) fuel pressure at the rail and I pulled the injectors and they all do spray at least a little. The engine is not firing at all.
My engine is a '01 and my PCM is a '98. I double checked all of my connections and my only wiring issue is that I do not have a EGR system so I can't plug in the Painless supplied connector. I've read where EGR can be deleted in the PCM but should the engine start if my donor PCM has it programmed in? I don't have the equipment to check the PCM I was going to get it tuned once I get it cranked.
I saw where someone mentioned a difference in the cam shaft positioning sensors on the later model engines. Is this true and would it keep the engine from starting? My harness connector plugged right in so I don't know if I need to pull the starter to check the sensor part #.
I do have good (55psi) fuel pressure at the rail and I pulled the injectors and they all do spray at least a little. The engine is not firing at all.
Last edited by 55chevy; 02-10-2008 at 12:57 PM.
02-10-2008, 12:54 PM
#2
egr wont prevent it from firing but will run real rough if the pcm is commanding an EGR event but no valve to control flow...wiring is a little different for 98 compared to 99+...if you have an 01 designed harness but a 98 computer that may be the problem...other than that you need to check for signal from crank sensor to PCM...good luck
02-10-2008, 06:40 PM
#5
I have 12 volts and ground on all the coils. I checked the crankshaft sensor and I have ground on yellow lead and 12 volts on the lt/green. The plug fits the sensor fine but I can not see the part # on the sensor without pulling the starter. Could it still be the wrong sensor? I'll have to pull the starter off to get to it.
I have checked the plugs and they are dry. I also checked the spark plug wires and they are not firing.
I haven't checked the cam shaft sensor voltages but I believe someone said the engine would crank but run bad if it was a problem.
I do have 4 gauge grounds - frame to body, frame to engine, and the Painless harness 4 black grounds and 2 black/white grounds are terminated on the engine block. The casing of the '98 PCM may not be grounded since I have it secured in a padded way, under the dash. Does the PCM casing itself need to be grounded?
Any more ideas, let me know. I'm still checking on what I can find from other post.
Thanks.
I have checked the plugs and they are dry. I also checked the spark plug wires and they are not firing.
I haven't checked the cam shaft sensor voltages but I believe someone said the engine would crank but run bad if it was a problem.
I do have 4 gauge grounds - frame to body, frame to engine, and the Painless harness 4 black grounds and 2 black/white grounds are terminated on the engine block. The casing of the '98 PCM may not be grounded since I have it secured in a padded way, under the dash. Does the PCM casing itself need to be grounded?
Any more ideas, let me know. I'm still checking on what I can find from other post.
Thanks.
Last edited by 55chevy; 02-10-2008 at 07:05 PM.
02-10-2008, 07:02 PM
#6
it will start with a bad cam sensor , but wont if something in the crank sensor circuit is messed up.....double check the main PCM grounds, on a stock harness there are 3 that are bolted to the back of the driver head....no fuel or spark leads me to believe it's ground problem....
02-10-2008, 10:12 PM
#7
it will start with a bad cam sensor , but wont if something in the crank sensor circuit is messed up.....double check the main PCM grounds, on a stock harness there are 3 that are bolted to the back of the driver head....no fuel or spark leads me to believe it's ground problem....
I'll pull off the starter tomorrow and double check the crank sensor since it is so hard to see and get to.
Thanks for all of the help.
Steve
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02-11-2008, 10:17 AM
#8
Finally!!!!!!!!!! Well I finally got it cranked. I found this message by John (Speartech) in an earlier post -
"Also, when you check voltages, you need to check them DURING cranking, not just with the key on. It's very common for people to hook up to an ignition switch terminal that is hot with key on but dead during crank.".
I got to checking my Painless universal fuse panel and my old (55) GM ignition switch last night and I could not find a place to pick up a power lead when the ignition was in both positions. I called Painless first thing this morning and ask where I could pick up that power lead. They said that on the old gm iginition switches, you have to strap ign1 and ign2 together and send that (using their pink ignition lead) to the fuse panel which in turn feeds their pink wire (usually their coil wire) to the pink PCM input. Well I did that and it cranked right up and runs great so far.
I'll heat cycle the new valve springs and run it again.
Thanks again for all of the help this past weekend.
"Also, when you check voltages, you need to check them DURING cranking, not just with the key on. It's very common for people to hook up to an ignition switch terminal that is hot with key on but dead during crank.".
I got to checking my Painless universal fuse panel and my old (55) GM ignition switch last night and I could not find a place to pick up a power lead when the ignition was in both positions. I called Painless first thing this morning and ask where I could pick up that power lead. They said that on the old gm iginition switches, you have to strap ign1 and ign2 together and send that (using their pink ignition lead) to the fuse panel which in turn feeds their pink wire (usually their coil wire) to the pink PCM input. Well I did that and it cranked right up and runs great so far.
I'll heat cycle the new valve springs and run it again.
Thanks again for all of the help this past weekend.
02-12-2008, 07:41 PM
#11
Thanks! I prolly wouldn't have made it without the LS1Tech forum. It's great. I was doing a complete body off restore when I ran across my LS1 in the spring of '04. I joined ls1tech shortly after that. I have had the car apart for 7 years total and hope to be finished in a couple of months. I finally got off my a$$ and got busy. Yes, those should be $ signs.
Anyway, it's great to have it running. I have a 3" Pypes exhaust all the way back with Patriot headers up front. I think it sounds great. I've beem a little dizzy smelling the sweet exhaust fumes the last 2 days.
Anyway, it's great to have it running. I have a 3" Pypes exhaust all the way back with Patriot headers up front. I think it sounds great. I've beem a little dizzy smelling the sweet exhaust fumes the last 2 days.
02-28-2008, 09:39 PM
#13
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i know it's been awhile since this thread was started. But i've got an experience i should tell you about so if it happens to you, you will know wtf is going on.
my '56 chevy 210 post, original EVERYTHING except: 283, B&M 144 blower, 100 amp alternator, Holley 4 barrel TBFI, MSD 6AL, electric fuel pump, good stereo, bla bla bla.
Anyway, I'm driving to Denver for a Super Chevy Show. About Colo. Springs the car dies for no reason. tow it to C.S. and change the electronic dist. for a points type. Runs well, gets me to Denver and home to Albuquerque. Didn't think much about it, 'till, I'm going down the freeway and it dies again. (this is months later). I just barely brush/touch the ignition key and it comes back to life, for a second, hold the key, just right and it runs again. But the key is HOT. Anyway, it turns out '55 '56 '57 ect. ALL the electrical current goes thru the ign switch, with all the extra stuff, ( F.I., computer, fuel pump, 100 amp alternator, ect.), the switch would get hot, expand, and lose contact, or arch, (which makes it HOTTER). Anyway, again, I rewired some of the elec. to bypass the switch and never had a problem again. So, i don't know how the painless harness is wired but it might a good time to check it out.
my '56 chevy 210 post, original EVERYTHING except: 283, B&M 144 blower, 100 amp alternator, Holley 4 barrel TBFI, MSD 6AL, electric fuel pump, good stereo, bla bla bla.
Anyway, I'm driving to Denver for a Super Chevy Show. About Colo. Springs the car dies for no reason. tow it to C.S. and change the electronic dist. for a points type. Runs well, gets me to Denver and home to Albuquerque. Didn't think much about it, 'till, I'm going down the freeway and it dies again. (this is months later). I just barely brush/touch the ignition key and it comes back to life, for a second, hold the key, just right and it runs again. But the key is HOT. Anyway, it turns out '55 '56 '57 ect. ALL the electrical current goes thru the ign switch, with all the extra stuff, ( F.I., computer, fuel pump, 100 amp alternator, ect.), the switch would get hot, expand, and lose contact, or arch, (which makes it HOTTER). Anyway, again, I rewired some of the elec. to bypass the switch and never had a problem again. So, i don't know how the painless harness is wired but it might a good time to check it out.
