Help! Won't start after cat bypass, new O2 sensor and valve covers
#16
Instructor
I hate to say it after it's already been mentioned, but double check the plug order. If you want to make sure you're at least getting fire, pull a plug wire off a cylinder and plug-in an extra spark plug. While gripping the plugwire by the boot head, hold the plug ground strap against bare metal on the chassis and have someone turn the key for a brief second while looking for spark. Repeat for each cylinder.
I hope it's something simple and not an ecu issue.
I hope it's something simple and not an ecu issue.
#17
Rennlist Member
"Now, she'll turn over and nearly run, but always dying, and then a pop of overfuelling."
Does this mean that your fuel pump is running? Do you have spark and fuel flow to the engine?
Does this mean that your fuel pump is running? Do you have spark and fuel flow to the engine?
#18
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I get the fuel pump whirr, and yes I have had a couple of pops after trying to operate the throttle whilst turning over the engine, so I am guessing a spark too. I wonder if the coils are vulnerable to voltage spikes. There's no emergency fuel cut off valve in these cars is there?
I have triple checked the plug wires, there are 3 lengths so you have to really try hard to mix them up. They are all connecting with that satisfying metallic noise. Anyway I think it would at least run with the wires mixed up because of the twin plugs.
In a flurry of excitement I remembered the fuel pump and DME fuses, but both are good, dammit!
I'm going to post the DME for testing today, thanks for the help so far.
Hope I havent killed my ABS brain too
I have triple checked the plug wires, there are 3 lengths so you have to really try hard to mix them up. They are all connecting with that satisfying metallic noise. Anyway I think it would at least run with the wires mixed up because of the twin plugs.
In a flurry of excitement I remembered the fuel pump and DME fuses, but both are good, dammit!
I'm going to post the DME for testing today, thanks for the help so far.
Hope I havent killed my ABS brain too
#19
Nordschleife Master
The coils have nothing in them that would be bothered . One old time fix for a bad coil was to spike it to try to get an open winding to arc itself back together . The ignition switch / transistor might not like being hit .
Not that I have seen .
Not that I have seen .
#20
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ECU tested: Update
OK, the ECU test report is just in with 'no fault found', with an extended overnight test pending.
So this is of course good news and bad news all at the same time! I am spared the horror of paying for an new ECU, but I am back with the mystery fault and a dead car.
So what next?
Any other stuff the welding could have damaged? I am still of course hoping that the welding damage is a red herring (which would be good news for my CCU and ABS brains) - although from what I have found out there is no doubt that welding can and does damage these systems sometimes.
I am going to remove the bypass and double check that it isnt blocked with something (I have kids..)
Would it run in theory with all the lower plug leads disconnected?
What is the best way to test that fuel is being delivered?
Its a 2 hour flatbed to the nearest Bosch hammer...thats probably the last resort.
So this is of course good news and bad news all at the same time! I am spared the horror of paying for an new ECU, but I am back with the mystery fault and a dead car.
So what next?
Any other stuff the welding could have damaged? I am still of course hoping that the welding damage is a red herring (which would be good news for my CCU and ABS brains) - although from what I have found out there is no doubt that welding can and does damage these systems sometimes.
I am going to remove the bypass and double check that it isnt blocked with something (I have kids..)
Would it run in theory with all the lower plug leads disconnected?
What is the best way to test that fuel is being delivered?
Its a 2 hour flatbed to the nearest Bosch hammer...thats probably the last resort.
#21
#22
Nordschleife Master
#23
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Yep, the place testing it say they can normally repair them for £150-200, but as the welding damge can in theory be pretty severe, I was bracing myself for an unrepairable ECU- used off ebay £500, new at £1200 - or needing to repair other systems too (boy do I miss my ABS lights playing up..NOT)
Always the optomist!
I cant think why anything has changed in the dizzy apart from some coincidental failure, but it was the lower leads I have messed around with - so I wondered if I could take them out of the equation at least.
Have I unplugged/knocked something in passing? Itching to get home and start looking around again..
Always the optomist!
I cant think why anything has changed in the dizzy apart from some coincidental failure, but it was the lower leads I have messed around with - so I wondered if I could take them out of the equation at least.
Have I unplugged/knocked something in passing? Itching to get home and start looking around again..
#24
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i definatly feel its something simple that you havent checked.
just a matter of what though obviously
if it doesnt run with the bottom leads connected then it would be the same with them disconnected
just a matter of what though obviously
if it doesnt run with the bottom leads connected then it would be the same with them disconnected
#26
Nordschleife Master
My crazy line of thought with yours is that an arm got zapped during the welding?
#27
Rennlist Member
Occam's razor says this may be it. I had a friend in college with one of those huge Oldsmobiles who couldn't get his car started and came to me in virtual tears wondering what the hell's wrong with his car. I looked around the vehicle and noticed that he'd backed the car into a dirt berm with the tail pipe stuffed into the dirt. Once we moved the car and cleared the tailpipe, the car started up immediately.
#28
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Johnny,
have you seen the OBD setup that Tore sells with the scantool software looks handy to have for situations like this, I intend to get one at some point. not really helpfull at the moment.
http://privat.bluezone.no/toreb2000/t-productsEN.html
my car is up on stands for the next few weeks, before you go replacing everything give me a buzz might be able to help.
cheers
Gary
have you seen the OBD setup that Tore sells with the scantool software looks handy to have for situations like this, I intend to get one at some point. not really helpfull at the moment.
http://privat.bluezone.no/toreb2000/t-productsEN.html
my car is up on stands for the next few weeks, before you go replacing everything give me a buzz might be able to help.
cheers
Gary
#30
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I'm with occam's razor...the cause of this when I find it will be another one for my own personal bonehead list I bet.
Gaz, that's a really nice offer, I'll let you know. I was wondering about a code reader too, but hadnt got around to searching, I think thats got to be well worth the 60 quid delivered for the discerning 964 owner.
Indy, yes it will, with occam in my garage...
Gaz, that's a really nice offer, I'll let you know. I was wondering about a code reader too, but hadnt got around to searching, I think thats got to be well worth the 60 quid delivered for the discerning 964 owner.
Indy, yes it will, with occam in my garage...