Hi there, I'm new here and need a little help trying to figure out my issue.
I've checked a LOT of things already and am looking for advice - similar situations that were resolved (hopefully).
My Audi is a 1990, 90 Coupe Quattro 1st Gen (pre-March 1990 with the Hitachi components instead of Bosch).
Maybe a month ago, I did a little trip of 150km up north to go see a Rallye. Everything was going fine on the way there and no weird noise or losses of power or anything of that sort.
Upon arrival, I started having issues - If I went past the 1/4 of the throttle, the engine would not catch up - If I remained a low throttle and idle - I could run - slowly.
I stopped at a gas station and checked a few things - Bought also a fuel defreezer (I'm in Canada, it was maybe -30 degrees Celcius that day !!) - Checked air box, vaccums lines, connectors, put back everything together.
We tried to move along - and slowly the issue got worse - up to a point were I couldn't even move the car - Idle was still fine.
Checked another bunch of things - added a ton fuel defreezer and let the engine run at idle for at least an hour (no if water there was - most likely was dissolved at that point).
Came back the next day - wouldn't start - hasn't kept idle for more than 5 seconds since - it is definitely trying but something is off.
Forwarding to the actual testing I did after I towed baxk the car back to my place.
What was tested/checked :
-Tried to pull the codes - but I disconnected the battery while trying to put a bulb in the cluster for the Check Engine light -So i guess they're gone since none were there.
-I did the output mode, aside from the injectors (didn't hear them click since didn't I needed to put it at WOT - IMPORTANT - Now if I run the output mode, it skips completely the injector part - tried 3-4 times and goes directly from the Fuel pump relay (which I hear) to the ISV. The do squirt seemingly fine since I pulled the rail and cranked the engine. Relevant that the output mode skips that part !?!?
-I have spark - that seem decent from the looks of it.
-I have gas - Fuel pressure is 90 PSI before FPR and 60 PSI after (not sure of that reading anymore but was on spec as per the Bentley).
-MAF readings are on spec as per the ones that can be obtained from a non-runnning car.
-TPS and idle switch also.
-Coil on spec - tried with a spare anyways.
-ISV on spec - tried also with a spare.
-Bypassed water coolant temp with another one - was tough to get resistance readings on it - Even though the ECU is supposed to read 20 deg Celsius if no readings are obtained (but it is somewhat sold up here so maybe ... jus maybe) so used another Audi one with proper resistance readings - same difference.
-Checked Ignition reference sensor on Flywheel - "dolly pin" is there and not gunked. Removed sensors (they were gunked and thought I had found the culprit) and tested with spares - Nothing.
-Checked distributor - a little bit dirty but nothing to be worried.
-Spark plug cables (I think were replaced not so long agao - looked pretty new) and spark plugs seem ok.
-Hall sensor readings are difficult to obtain since the refer to a special tool to check it ... And the car need to be running for 1 part and I do have spark - from what I understood - I wouldn't if the hall sensor was defective ?
-Unplugged wiring harness from the ECU and checked for corrosion - reseated/reconnected it.
-Check timing belt (was replaced 12k km ago from the previous owner, thought might've been loose and jumped a few tooth) - everything was tight and on spec (wasn't able to find the TDC mark on the flyheel though).
That's where I'm at ... Any ideas because I'm about to change bit by bit in a crab shoot to try ot fix things.
I ordered another ECU from a European fellow and am waiting for it to test.
Questions I have :
-If a TPS is defective - would the car still start ? I think so bu want to make sure.
-Would a defective MAF prevent the car from starting ? (don't think so but want to be sure)
-Would a defective Hall sensor prevent the car from starting while there is spark ?
-Is the fact that the output mode of the fault diagnosis skips the Injector part relvant ?
-034 injector kit (stock) was put in bypassing the resistor pack - Can somebody mess that up ? Anybody has stories of them failing ?
Anything would help ...
Thanks
I've checked a LOT of things already and am looking for advice - similar situations that were resolved (hopefully).
My Audi is a 1990, 90 Coupe Quattro 1st Gen (pre-March 1990 with the Hitachi components instead of Bosch).
Maybe a month ago, I did a little trip of 150km up north to go see a Rallye. Everything was going fine on the way there and no weird noise or losses of power or anything of that sort.
Upon arrival, I started having issues - If I went past the 1/4 of the throttle, the engine would not catch up - If I remained a low throttle and idle - I could run - slowly.
I stopped at a gas station and checked a few things - Bought also a fuel defreezer (I'm in Canada, it was maybe -30 degrees Celcius that day !!) - Checked air box, vaccums lines, connectors, put back everything together.
We tried to move along - and slowly the issue got worse - up to a point were I couldn't even move the car - Idle was still fine.
Checked another bunch of things - added a ton fuel defreezer and let the engine run at idle for at least an hour (no if water there was - most likely was dissolved at that point).
Came back the next day - wouldn't start - hasn't kept idle for more than 5 seconds since - it is definitely trying but something is off.
Forwarding to the actual testing I did after I towed baxk the car back to my place.
What was tested/checked :
-Tried to pull the codes - but I disconnected the battery while trying to put a bulb in the cluster for the Check Engine light -So i guess they're gone since none were there.
-I did the output mode, aside from the injectors (didn't hear them click since didn't I needed to put it at WOT - IMPORTANT - Now if I run the output mode, it skips completely the injector part - tried 3-4 times and goes directly from the Fuel pump relay (which I hear) to the ISV. The do squirt seemingly fine since I pulled the rail and cranked the engine. Relevant that the output mode skips that part !?!?
-I have spark - that seem decent from the looks of it.
-I have gas - Fuel pressure is 90 PSI before FPR and 60 PSI after (not sure of that reading anymore but was on spec as per the Bentley).
-MAF readings are on spec as per the ones that can be obtained from a non-runnning car.
-TPS and idle switch also.
-Coil on spec - tried with a spare anyways.
-ISV on spec - tried also with a spare.
-Bypassed water coolant temp with another one - was tough to get resistance readings on it - Even though the ECU is supposed to read 20 deg Celsius if no readings are obtained (but it is somewhat sold up here so maybe ... jus maybe) so used another Audi one with proper resistance readings - same difference.
-Checked Ignition reference sensor on Flywheel - "dolly pin" is there and not gunked. Removed sensors (they were gunked and thought I had found the culprit) and tested with spares - Nothing.
-Checked distributor - a little bit dirty but nothing to be worried.
-Spark plug cables (I think were replaced not so long agao - looked pretty new) and spark plugs seem ok.
-Hall sensor readings are difficult to obtain since the refer to a special tool to check it ... And the car need to be running for 1 part and I do have spark - from what I understood - I wouldn't if the hall sensor was defective ?
-Unplugged wiring harness from the ECU and checked for corrosion - reseated/reconnected it.
-Check timing belt (was replaced 12k km ago from the previous owner, thought might've been loose and jumped a few tooth) - everything was tight and on spec (wasn't able to find the TDC mark on the flyheel though).
That's where I'm at ... Any ideas because I'm about to change bit by bit in a crab shoot to try ot fix things.
I ordered another ECU from a European fellow and am waiting for it to test.
Questions I have :
-If a TPS is defective - would the car still start ? I think so bu want to make sure.
-Would a defective MAF prevent the car from starting ? (don't think so but want to be sure)
-Would a defective Hall sensor prevent the car from starting while there is spark ?
-Is the fact that the output mode of the fault diagnosis skips the Injector part relvant ?
-034 injector kit (stock) was put in bypassing the resistor pack - Can somebody mess that up ? Anybody has stories of them failing ?
Anything would help ...
Thanks
Comment