hondacowboy Posted January 31, 2012 Report Share Posted January 31, 2012 Hi I feel I needed to put this out here because of the frustration of 3 long months and the hole in my pocket that I didn't need. My daughters car a 1.6L EFI 93 hatch had an intermitant fault. The problem The general experience was it would stagger to a stop as if running out of petrol, after varing amounts of "stopped" time it would start, run, drive and after varying amounts of "drive" time it would stop and the cylcle would repeat itself. The trial and terror At the time of stopping I had replaced fuel filters, checked sensors, had the alternator checked, found out (from this forum) I could interigate the CEL system, it threw different codes every time but always to do with engine speed hmmmm, replaced distributor, would have replace the crank sensor (if I could find it), and just generally wanted to take a 10 pound hammer to it. The A/con and cooling fan were also operating intermittently replaced relays almost pulled the fan apart, pleanty of luck but all bad. Then it wouldn't start at all so I gave my daughter my car and had it towed to my place Logan City (Chermside to Logan $75.00 Mobitow) Now instead of travelling to Chermside to rescue her I could work on it full time. Yep did all that other work beside the road during that scorching hot summer last year early 2011. The showdown After a extra good look I found a broken airbox sensor conector drove the car for my whole break and no problem Gave it back and got a call that night, car broken down ferny hills. Swapped cars towed it back to Logan again. Car would not start at all. Left it for a day would not start. Left it another day no go. The discovery Got home after night shift and it atarted by this time nothing surprised me but this time I noted that the engine mounts were a little soft and there was probably a little too much engine rock in when driving, but so what. I took it for a drive was bit rough with the clutch (tired of looking at this car) and the engine stalled at the end of my road it did start, but seem to be missing when I rode the clutch in and out hmmmm. Back in the carport. Engine still running. Poped the bonnet and started checking connectors that I had already checked thinking some thing is loose. I grabbed the engine loom that disappears back into the firewall to the ECU to push it out of the way and the engine stalled. The Conclusion CEL codes were telling me the ECU was loosing the engine speed indication along with 2 other codes of similar ilk that I can't remember. Found 4 broken wires in the engine loom to the ECU. 3 going from the Distributor to the ECU - CEL codes for engine speed etc 1 from the temp sensor to ECU that stops and starts the cooling fan to maintain engine temp, which also effects the A/con fan sequence. Wiring in cars more than 15-20 years old will become brittle they don't last for ever. So maybe a vigourous wriggling of the engine bay wires may reproduce your problem before the torture begins. The Cause The engine loom was constanly being kinked by engine movement (a design fault) and since the engine mounts will get sloppier over time it worried the loom and broke the wires inside the insulation. The fix Check all the wires from device to ECU (unplug connector to ECU) with Multi meter Replace broken ones by running new ones on the outside and tape them up good. Start car check CEL Have beer and hope the other wires hold out. Have a nice day hondacowboy Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted January 31, 2012 Report Share Posted January 31, 2012 Well done! Subtle problems like those are the worst. The engine mounts on the Daewoo Nubira (we were given for free... says a lot! ) were so badly designed it would pull the top radiator hose off. That taught the family to drive smoothly..:laff: Quote Link to comment Share on other sites More sharing options...
parrot Posted February 1, 2012 Report Share Posted February 1, 2012 I had a very similiar experience in my AE86. It would start and run perfectly, and then cut out randomly. Could be sitting in traffic, driving along, whatever. Or you would drive somewhere and park, then on return the car would not start. Come back next morning, and it would start as if nothing had happened. ECU would throw up no codes, changed fuel filter and random sensors, ignitors and ECU's etc which I fortunately had spares for, so minimal expense. Problem remained unchanged. Had our first child, and after a few unpleasant experiences, car was parked up in the shed and left and a new car purchased. Eventually (a few years later) I decided to look into it. Only after methodically working my way through the Toyota 4AGE Engine diagnosis manual did I eventually discover the cause. When I did the conversion, I spliced a RWD engine loom into the factory 4AC loom. It ran perfectly for over 10 years until this problem. Converting the loom required introducing an injector circuit including an EFI relay. The factory sited this in the junction box at the driver footwell, and the 4AC junction box is identical just without the relay and wires. After running the wires, soldering everything up and installing the relay, I realised the lump of solder was preventing the terminal from fitting within the plug. Simple solution, cut out the little clip that retains the terminal within the plastic plug. 10 years later, the wire loosened off sufficiently, without the clip to keep it located, that it was making intermittent contact with the relay. No contact, no injector circuit. I learned some very valuable lessons. Do it right first time, and don't be quick to blame sensors and ECU's which rarely fail without human intervention. In an ECU controlled car, the wiring is everything. Quote Link to comment Share on other sites More sharing options...
hondacowboy Posted February 4, 2012 Author Report Share Posted February 4, 2012 Well done! Subtle problems like those are the worst. Hi Yeah thanks. I will add the details of the car to help the search process. Quote Link to comment Share on other sites More sharing options...
7shades Posted February 4, 2012 Report Share Posted February 4, 2012 As a closet Volvo enthusiast, I can relate. A lot of European cars of a certain vintage all have government mandated biodegradable wiring insulation. (brilliant idea that) Volvos especially have a metric f*ckton of wiring, relays, modules, fuses... All interconnected, and they ALL fail. Often. Troubleshooting down to the singular fault is an absolute nightmare. Quote Link to comment Share on other sites More sharing options...
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