Working on. 99 tahoe 5.7 and it had a blown head gasket. Tore everything down and rebuilt. Tahoe sat with gas in tank 3 years. Emptied gas and have checked spark fuel and airflow. Timing seems ok but distributor was replaced before blown head gasket and Tahoe was purchased. It throws a code for p1345 and p0108.
Cranks but does not start unless pressing on gas and rough idle . Any suggestions?
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wjburken
Supporting Member
How far down did you tear it down?
Was that before it sat for 3 years or recently?
Was that before it sat for 3 years or recently?
Down to the heads, to replace the gaskets. And replaced timing gears and water pump because water pump went. that caused the blown head gasket. And replaced heads recently after purchasing. Buddy sold it because he didn’t have time to work on it and it sat for three years
My buddy thinks it’s clogged injectors causing it and possibly map sensor. I replaced map sensor with cheap one and still was throwing the code. I bought cheap one so I could use the gasket because I wasn’t sure if oem was bad or just the gasket. Gasket was in bad shape. But after trying new map sensor and gasket on old oem sensor. It was still throwing p0108 code. The p1345 my buddy believes that just needs adjusting of distributor with his scan tool and wouldn’t prevent it from starting? My question is if there was a vacuum leak would I throw a code for the map sensor or a lean bank code?
Moved this to the engine and drivetrain section for more focused exposure.
Joseph Garcia
Supporting Member
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Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.
east302
Full Access Member
The P1345 (cam/crank sensor correlation) needs to be set at 0 degrees (plus or minus two) with a scanner after removing the distributor. It won’t trip the code until it’s something like 13 degrees out of spec, so it could (maybe?) be part of your issue. I’d set it just to check it off of your list.
If you don’t have a good ($) scanner like a SnapOn or a Tech2, you can set it using a Bluetooth OBD adapter and an app like DashCommand. You’ll have to buy their extended PID package, but total cost is probably in the $50 neighborhood for all of it. The PID that you’re looking for is the “CMP Retard” or something like that. Here’s a link:
www.gmt400.com
One workaround, just to see if it helps, is to loosen the distributor hold down clamp and twist the whole cap until the screw tab is almost hitting the intake. That’s usually close to zero degrees, but you have to get the scanner to know for sure.
Borrowed from the internet, but when it’s first stabbed and seated at #1 TDC compression, the rotor will point to the #8 triangle and the housing will be parallel to the intake. When setting the CMP Retard, twist until the distributor cap’s screw tab on the left is almost hitting the intake, maybe within a 1/16 to 1/8”.
The factory manuals have the diagnostic procedures for each DTC. Here is the one for P0108 for a 98, it’s probably the same for 99. The rest of the manuals can be downloaded below. I don’t know if they have 99, go with 1998 if they don’t. Alldatadiy.com is another option as it has the exact same information - they just took the GM manual and put it in a digital format.
www.gmt400.com
And last, have you checked the fuel pressure? It sounds like you’d have gotten the lines clear by now, so any junk fuel should be out of there. The test port is on the fuel line above the intake. Spec is 60-66 psi with key on, engine off. See if it hits that and then holds with key off.
Holding the gas down temporarily stops or reduces injector flow (clear flood mode) so you may have a leaking injector which should show up in your pressure test.
Another thing, if the coolant temperature sensor is flaking out, it’ll cause the computer to call for too much fuel (particularly on hot starts) and cause hard starts. A scanner can show the sensor’s output. It should be ambient when cold and up to the thermostat setting when hot. That’s the sensor by the thermostat.
If you don’t have a good ($) scanner like a SnapOn or a Tech2, you can set it using a Bluetooth OBD adapter and an app like DashCommand. You’ll have to buy their extended PID package, but total cost is probably in the $50 neighborhood for all of it. The PID that you’re looking for is the “CMP Retard” or something like that. Here’s a link:
Scanner Tool To Set The Timing????
Wanted to post my experience doing this, I used a cheap clear bluetooth ODB scanner (Foseal) and the Android DashCommand app, with the PID unlock for my truck year '97 ($10 for app and $10 for year unlock). Had to add PID Cam Retard CKP / CMP Correlation to the data grid on app. Spec is +2 to...
www.gmt400.com
One workaround, just to see if it helps, is to loosen the distributor hold down clamp and twist the whole cap until the screw tab is almost hitting the intake. That’s usually close to zero degrees, but you have to get the scanner to know for sure.
Borrowed from the internet, but when it’s first stabbed and seated at #1 TDC compression, the rotor will point to the #8 triangle and the housing will be parallel to the intake. When setting the CMP Retard, twist until the distributor cap’s screw tab on the left is almost hitting the intake, maybe within a 1/16 to 1/8”.
The factory manuals have the diagnostic procedures for each DTC. Here is the one for P0108 for a 98, it’s probably the same for 99. The rest of the manuals can be downloaded below. I don’t know if they have 99, go with 1998 if they don’t. Alldatadiy.com is another option as it has the exact same information - they just took the GM manual and put it in a digital format.
88-98 Service Manuals
Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...
www.gmt400.com
And last, have you checked the fuel pressure? It sounds like you’d have gotten the lines clear by now, so any junk fuel should be out of there. The test port is on the fuel line above the intake. Spec is 60-66 psi with key on, engine off. See if it hits that and then holds with key off.
Holding the gas down temporarily stops or reduces injector flow (clear flood mode) so you may have a leaking injector which should show up in your pressure test.
Another thing, if the coolant temperature sensor is flaking out, it’ll cause the computer to call for too much fuel (particularly on hot starts) and cause hard starts. A scanner can show the sensor’s output. It should be ambient when cold and up to the thermostat setting when hot. That’s the sensor by the thermostat.
Wow so many good tips. Thank you so much I’m gonna take a whack at it again this weekend. Last I checked my fuel pressure was holding around 50- 60 psi key on so maybe your right about a injector buddy said he had just replaced the injectors but but all is possible after sitting as long as I did lol I planned on removing intake to get to them just to clean after sitting. I’ll take a look again at the distributor and map sensor this weekend and report back. Thanks again
