Zan, No, I was not cranking when checking - I will try that. Ernie, I checked the crank sensors yesterday, as I was around that area trying to see if the a/c would cut in. - Thanks for your support. I am starting to think I will have to call in the local service guys.
I have now hardwired both pumps and they come on. Car still won't start. How do I check I am getting a spark without removing the plugs ?
Easiest way is to remove a plug wire, Put a screwdriver tip in the end, lay the screwdriver on a metal part of engine or frame keeping the shaft slightly off the metal creating a gap. have someone crank the engine, you should see a spark. Mark Make sure there are no fuel leaks first!!!!!!
Any spark plug will do to check for a spark,even one out of a lawnmower, this should have been checked first,to check for injector triger you should realy use a noid lamp but for diy purposes you could rig up a couple of wires to a bulb,it may be just flooded to death,i assume the car is cranking over at a good rate,if not get some charge in the battery,as for spark and injector triger ok checking the fuel pressure is more difficult without the right tools, you may get some idea whats going on if you remove a plug,is it wet,dry, cheers Dale.
Behind either the passengers or drivers seat are leather covered "boxes". Remove them and you should see a black plastic push button. Turn the ignition on and push the black button. The check engine light should flash you a four digit code, (example..4-1-2-1) this will tell what is wrong! Probably a TDC or cam timing sensor they always are going bad. I have the table or it is in the repair manual that tells you what the code means. Talks minutes to do.
Thanks Zan, Did as you suggested with the screwdriver I have a spark on 1-4, nothing on 5-8. What next ? All connectors have been cleaned & reseated.
Thanks Zan, Did as you suggested with the screwdriver I have a spark on 1-4, nothing on 5-8. What next ? All connectors have been cleaned & reseated.
Hav you checked the fuses?, each ecu has it's own fuse and relay, if fuses are ok, try swapping relays and recheck spark. If you have tools try swapping coils too. If it doesn't change I'll dig out my 2.7 diagnostics Mark
zan, I can't identify the fuses & relays in the owners manual. Closest I get is the fuses 14 & 18 ignition/injection system and relay D & L, actuation of the injection nozzles. I may be able to borrow an oscilloscope to check what I am getting at the inputs to what I believe are the ignition power modules. There are 2 cable connections there a 3 pin and a 5 pin as well as the 4 ignition wires.
Time for a recap of where I am. Car will not start - splutters and dies after a few seconds. No spark on cyl 5-8 All fuses OK (in the passenger well box) Connectors on everything in sight cleaned and reseated Thermocouples ECUs disconnected Motronic box connections cleaned and reseated. Light is fading here in the UK and I have pushed the car back into the garage. Next steps fo rthe coming week Try to understand what I should see on the inputs to the ignition lead modules when cranking the engine Swap 1-4 with 5-8 ?? Call in the service guys. I must close this soon or the battery will go dead with the number of times I am trying to start the car. Thansk for all your help. john
The two ign/coil modules are the same, remove them and install on opposite side, then see if spark changes bank
I'm a 348 newbie too... but following with great interest. Would it make sense to swap the main ECU's (behind the seats) at this point? It's an easy process and requires no mechanical "know how". Wouldn't a swap and resulting failure on back 1-4 (and spark on 5-8) confirm the ECU is the problem? Before tearing too much stuff apart, it seems like another easy diagnostic test. -Daniel
Most probably the fault lies with the crank sensor for the 5-8 bank. it is located on the front lower part of the engine next to the crank pulley where it gets it`s signal. the 348`s and 355`s were known to have problems with the plug for the sensor backing out of the connector or just poor connections. access is under the car, front of engine and remove the cover shield for the belt area. there you will see the crank pulley with two sensors on on top and one on side of crank pulley. check the connectors for poor connection of broken wires. really the sensor should be checked with an osillicope but if you have no choice, remove and swap the sensors. if 1-4 bank fails, you have found your problem. good hunting....best regards, jim
note: this type of fault will not show up as a computer fault (or code) due the the engine thinking the key is on but not started, (computer senses connection but no signal) so unfortunatly to check for a failed sensor you must test it. jim
Could also be the coil pack for that bank or a connection. that would be rare, but possible. I have yet to see a ecu fail unless hit by lightning. regards, Jim
Thans guys for the additional info. If it turns out to be the crank sensors I will kill myself. I was cleaning around the a/c pump at the weekend which sits next to the upper sensor. I thought I had re-seated these when trying to diagnose the faults, but maybe it was just the lower one ? Anyway, I have now borrowed a scope to continue diagnostics I will keep you posted as the saga continues. I have complete confidence that an amateur like me & the good guys on FChat will resolve this. Does anyone know.... If I unplug the crank sensors and crank the engine should I see a signal from the output of the sensor I will be using a dual trace scope to compare 1-4 & 5-8 simultaneously. Also, with the power modules, I notice a 3 pin & 5 pin connector. What do these do ? Anything I can check on the inputs. I could swap the power modules, but as the good Doctor says, it is rare for these to fail. John
Jim, Clarification....If the car was running and THEN dies won't you see this error code on the 2.7 MIL or the SD-1 or SD-2? I understand your point if the car is dead and you are trying to diagnose it. This is the same with the cam position sensor too correct?
true - you will get a code if the vehicle looses the signal during engine operation. You will also develop the code if you leave the key on without running for a short period of time. the computer is setup to ignore the error because it knows the car may not be running. To verify fault through sd1 or 2 you must erase the error and try to start while monitoring the sensor outputs. as for the cam position sensor, any error noted there would be valid due to the fact the engine does not need that sensor to run and the error setting rational is different. the cam position sensor only assists with start up to fine tune location of cams in relation to crankshaft for faster, smoother startup. you can unplug the cam sensor and the engine will still start although it will crank longer. once it figures out cam position based on WHICH crank sensor is active. good to here the problem is solved....... best regards, Jim
