Diagnostics on a 2000 Firebird.

TransAmDan

Forum Admin
Staff member
There was a car that came to the Southsea cruise around 18 months go. A convertible firebird. We did have some discussion on it some time ago on what particular model it was.
Anyway it failed its MOT on emmisions. The guy only lives in Portchester, so he got my number from Kev with the mustang. I popped down there with my scanning software, he has a few codes like crank position error, engine misfire.
Running on tick over I could see the lamda sensors were switching, so they didn't appear to be at fault.
Ran a 'cylinder test', I can turn off each fuel injector. Cycles around turning #1 injector off, car felt lumpy, turned it back on and moved onto the next injector. Now #2 made no difference to the running of the car.
It appears #2 isn't working right, and with popping occationally coming from the exhaust on tick over then the injector is probably working fine, but not igniting until it gets heat in the exhaust. So its a spark issue.
Coil packs dont tend to go. I could just get my hand in there to swap HT leads from #1 to #2. Made no difference, so perhaps the plug.
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The engine bay is all original, so getting to #1 plug was a pain, good job it wasn't #8. I have so much room in my engine bay its a 15mins job to change all plugs, I think it would take 3 hours with tiny hands on this one.

He has a garage that does the work for him so at least there is some come back if something dosn't go right, think they have a slot in September. The car has 50k miles one it, so could even be original plugs.

I guess a lot of garages will be busy now as MOT extentions are no longer in play. So now there is double the amount of people trying to get an MOT,.
 

TransAmDan

Forum Admin
Staff member
Yes, they are on the top. To take one off you need to take off the assembly of 4 as they are mounted on a frame. I have my old spare ones that we could use for testing this. The coil packs gets its earth through the frame. So i cant just hold it in place as the 4 pin connector wouldn't reach and no earth. Its not impossible to take the frame off. Maybe that will be something to try once changing the plugs. He has no record that the plugs have ever been changed.
 

TransAmDan

Forum Admin
Staff member
Yeah you would think it would be straight forward, I dind't have tools with me, as it was more of a disgnosis session. There are bolts that hold the coil packs on, around 6 of them perhaps (only have 2 or 3 on mine) the ones behind the aircon pipes are a right pain. I tihnk taking the coil packs off is on par with extracting the spark plug.

It was good to chat to the guy though. Once he has it through the MOT I'm sure we will be seeing him more often. He said thats its always popped since he has it and thought it was a modification. Sounds like he has been running on 7 cyclinders in all the time he has had it.
 

saleen 192

Core Member
was the miss fire code ie p0302 for cyclinder no2 or p0305 for cyclinder no.5 if so you only need to look there or was it a generic code for a missfire??
ie generic po300
 

AmericanThunder

Super Moderator
Yeah, had one go on a 4th gen V6 Camaro. It used 3 coils in a spark wastage layout. Middle one blew and took out 2 cylinders.
 

Will

Core Member
I once had one fail on a straight four 2.3 Ford Galaxy MPV. They have two packs, each serving two cylinders. One pack failed giving no HT output just on one cylinder. Funny thing is, the ECU didn't even throw up a code or put an engine light on!
 

renchero

Active member
50k original plugs that's where i would start if one has not been firing all the time he's had it. it's bound to be fouled even if its not a plug fault original. i would also do a compression check wile the plug as out.
is it not possible to rig up a bench test on the coil pack
 

TransAmDan

Forum Admin
Staff member
50k original plugs that's where i would start if one has not been firing all the time he's had it. it's bound to be fouled even if its not a plug fault original. i would also do a compression check wile the plug as out.
is it not possible to rig up a bench test on the coil pack
I have spare coil packs he can use to swap out to diagnose. Its only a 4 pin connector, so could be powered up on a bench supply with a lead and spark plug.
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When chatting to the guy, I said it would be good to do s compression test while the plug is out.

He was over the moon with the diagnostics that was done, but would like his garage to do the rest like changing plugs etc..
 
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