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tims auto repair
tims auto repair, mechanic
Category: Pontiac
Satisfied Customers: 15474
Experience:  owns a repair shop...25yrs
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I have 1997 Pontiac Grand Prix 3.8. I had a head gasket and

Customer Question

I have 1997 Pontiac Grand Prix 3.8. I had a blown head gasket and lost compression at cylinders 1&3, check engine light was flashing with a code of P300 random misfire. replaced head and gasket with a new one. Put it back together and ran great. Next morning put a crankshaft seal in to replace the leaky one and tried to crank it afterwards and it would start. I then replaced the crankshaft sensor, cam shaft sensor, fuel rail & regulator, plenum and all its sensors (MAP, MAF, throttle body, TPS, wires, plugs, ICM, coils, clean injectors and seals , new fuel pump, O2 sensors, checked all fuses.
JA: Does the light stay on, or does it blink?
Customer: It has not started , I have fire at the plugs , compression 149 in cylinders, small backfire from injectors, )dtc no codes, crank but will not start
JA: Are you fixing your Grand Prix yourself? What have you tried so far?
Customer: yes, just sent you everything that has been done, it is a lot
JA: Anything else you want the mechanic to know before I connect you?
Customer: did you get my opening statement
Submitted: 1 month ago.
Category: Pontiac
Customer: replied 1 month ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Cary York replied 1 month ago.

Hi, I’m Cary and I’ll be helping you today.
Please understand that I can't smell, hear, or touch the vehicle, so patience is appreciated. Before leaving the site make sure and leave me a rating. You can still reply to me as many times as needed, even after the rating..

You replaced the crankshaft seal in the front or rear of the engine?

Customer: replied 1 month ago.
Front
Expert:  Cary York replied 1 month ago.

Sorry I have to go. I will opt out so another expert can help.

Expert:  tims auto repair replied 1 month ago.

Hi, My name is ***** ***** for the delay.

I will do my best to assist you.

will it fire with a prime?with a little fuel or starting fluid into the throttle body?

Customer: replied 1 month ago.
No, check that through throttle body, has fuel at pressure regulator Schrader valve., Gas coming into fuel rail and out, has compression 149, plugs has fire.
Expert:  tims auto repair replied 1 month ago.

what does it do when you prime it?will it back fire or anything?

Customer: replied 1 month ago.
Just spin over, there is a small backfire ignite, the starter fluid causes it to spin a little higher pitch until it burns off. The rockers arm are move the valves with the turn of the engine
Expert:  tims auto repair replied 1 month ago.

ok..so,you have a spark,but it wont even fire with the prime?correct?

Customer: replied 1 month ago.
it seems like timing, but the chain is turning the cam, have spark, have gas, have air, no codes, no DTC, crank but no start
Expert:  tims auto repair replied 1 month ago.

you need to replace the ignition module under the coils..

the module is bad that is why it is firing out of time

Expert:  tims auto repair replied 1 month ago.
Customer: replied 1 month ago.
I changed that also with a different set of coils, to get a different result, but it is unchanged and I am getting the same response
Expert:  tims auto repair replied 1 month ago.

it isnt the coils,,but the module under the coils..

if you are certain the module is good,then it has jumped time on the chain,,but it isnt likley sense it has this good compression.

there is no reason for it not to fire with a prime if it has a spark..if the ignition module is good and the engine is in time

Customer: replied 1 month ago.
You are so right, that's what is so puzzling. The ICM change did make a difference.
Expert:  tims auto repair replied 1 month ago.

try another icm

Customer: replied 1 month ago.
I will, but the coils all 3 are firing with strong spark, new cam sensor is in. A chain should not jump time and the PCM be fine right
Expert:  tims auto repair replied 1 month ago.

i understand it is firing,but it must be firing at the wrong time

Customer: replied 1 month ago.
I agree, I will change it again for the 3rd time. Then what! I can't believe it's the chain or PCMM. DO YOU?
Expert:  tims auto repair replied 1 month ago.

well..the chain isnt lilely,it has too much compression to be out on the chain,,i would think.

Customer: replied 1 month ago.
K I will change the ICM again and let you what happens, I don't think it's the injectors because spraying into the throttle body and/or intake yields the same result. Which should cause it to run for little while then cut off. But spraying it does not make it crank and there is some small intermittent back and vaper gases that escapes from the injectors.
Expert:  tims auto repair replied 1 month ago.

yes..please do

thanks

Expert:  tims auto repair replied 1 month ago.

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