I've had my 1992 golf mk2 GTI for about 5 months. A month or two the car broke down when idling at a stop sign. It would crank perfectly but it wouldn't start. Had it towed to my local German auto specialist, and they found that my spark plugs were quite black and worn. They replaced them and the car ran fine, then the next day when trying to start my car up in the morning, (about 5 Celsius weather) the same issue arose. It would crank but wouldn't start. The last owner had installed a block heater, so I decided to plug it in, wait, and attempt to start it. this time the car started. Their notes were: stated “car hard to start just cranks, with full throttle it will just catch and eventually it will run . checked air flow meter , all in spec coolant temp sensor ok check plugs , very black and wet with fuel. replaced. runs way better now .” This issue consisted until I brought it back to the to the shop recently, where they spent over 7 hours testing everything they could think of: They then swapped out my ECU with a one they had in shop that resembled mine (but not the exact part) and it surprisingly would start, cold (rough). After that, they decided to put my original ecu back in which magically allowed the car to start again. They said the issue could have been faulty connections or corrosion or something. This is the service notes left by the mechanic from the second trip: "The engine will not start cold. -Test ignition system: There is ample spark present - suspect weak spark? Check distributor hall sender, cap/rotor OK. Replace ignition coil and test: still no start. - Replace ground connectors at coolant flange as they are poor. Still no start. - Unplug O2 sensor, no start. Unplug mass air sensor, no start. - Test fuel system: pressures OK - in-tank and main pump are working. - Noting fuel smell at tail pipe - seems to be too rich when trying to start. Remove spark plugs: found to be fuel soaked. Clean plugs. Still no start. *this fuel contamination only happed the once. - Engine will randomly start. When cold again, no start. - Suspect ECU - check and clean connector and terminals. Still no start. Connect known good used ECU, engine tried to start but no. Connect original ECU, engine started. When engine cooled off again, no start. - after trying to diagnose the problem for these few days the car is now starting cold every time. Cannot continue diagnostics now. The engine may not start again. The problem is inconclusive." After this, I drove it for about five days where it would start up perfectly each morning in 2 degree celcius weather and ran great. Then, suddenly one morning it would just crank and never start. So back to square one. Is there anything here that could have been overlooked? Anything helps, it seems it will start fine once the engine has been plugged into a block heater for atleast 2 hours. (apologies for so much info)
Feel sort of stupid suggesting this as I'm no mechanic, but I've had to try and resolve some issues with my own cars over the years which've got me looking into some things in a bit more depth... one of them was batteries. I'm guessing you're maybe USA or Canada, not Europe / UK and being 1992 it's a Digifant car? If so, did it come to you from a different State / climate? I'm wondering if it is as simple as your battery not being up to the job for where you are now, it might be that its Cold Cranking Amps are now maybe insufficient (but might've been perfectly adequate in a warmer place)? If the block heater being reconnected helped, maybe it brought the oil temp. up to a point that it allowed the battery to have sufficent power to more easily turn things over? If you are in a non-UK / European market you possibly don't use the same industry standard terminology and this'll mean nothing, but here the CCA is usually clearly indicated on the battery... the higher the number the greater the abilty to cold start. If you don't use that form of rating I'd imagine the local term wouldn't be hard to find out and go from there.
Yes I think my injection is digifant 2? I’m 80 percent sure. The car was manufactured in mexico. I live in Canada, before I purchased the car it spent time in Saskatchewan which endures very cold winters, probably reasoning for the block heater. I’ll have to check the grade on the battery though for sure.
If Diji 2 you should have a plastic water fitting front centre of the head ,it has 2 sensors ,one is blue if faulty the engine gets no info to establish the engine it is cold , it effects timing and starting fuel if I remember correctly ,I had a failed one or I thought but turned out to be a faulty wire in the engine loom which I replaced ,the only way it would start was by advancing the timing but once warmed up for obvious reasons it didn't run well . Not an expensive part and worth changing just make sure you replace with genuine as some say the aftermarket ones are not very good ,cheers.
Okay Okay thanks for the insight. The last owner left me with a fair amount of parts and i think i had saw a blue sensor, I forget if it was sealed or not. I’ll try and replace it today and see if it affects the start.
Checked the sensor and replaced with no luck. I brought it back to the shop and they took another shot at testing components with no result. You said yours was a faulty wire? Maybe thats my issue.
If it's very rich, the fuelling might need to be adjusted, as per the famous Rubjonny Digifant setup guide.
Greetings from Alberta - here you go https://clubgti.com/forums/index.ph...ose-and-tune-your-mk2-digifant-gti-8v.124949/
