cold start system LH Jetronic
02-19-2002, 05:05 AM
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cold start system LH Jetronic
hi all
first, many thanks for all the help given so far get my euro 928s up and running.
does anyone know who the cold start system works on a 1984 euro s with LH Jectronic injection?
my car starts from cold fine...runs at a fast idle, then slows down to a normal idle....aux air valve doing its job (previously checked) but the car is running very very rich. if i drive it i can manage 40mph max with clouds of black smoke. exhaust extremely sooty.
what controls the mixture on warm up? are the injection pulses just lengthened, or is there another cold start injector somewhere?
maybe the mixture setting is wildly out.
is there a check proceedure for this problem?
checked twin sensor on thermostat housing..high res at cold low at hot (4KR -> 500R)back to ecu cable headers.
regards
johnb 1984 euro 928s
first, many thanks for all the help given so far get my euro 928s up and running.
does anyone know who the cold start system works on a 1984 euro s with LH Jectronic injection?
my car starts from cold fine...runs at a fast idle, then slows down to a normal idle....aux air valve doing its job (previously checked) but the car is running very very rich. if i drive it i can manage 40mph max with clouds of black smoke. exhaust extremely sooty.
what controls the mixture on warm up? are the injection pulses just lengthened, or is there another cold start injector somewhere?
maybe the mixture setting is wildly out.
is there a check proceedure for this problem?
checked twin sensor on thermostat housing..high res at cold low at hot (4KR -> 500R)back to ecu cable headers.
regards
johnb 1984 euro 928s
02-19-2002, 05:28 AM
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I know it sounds stupid....but first thing to check would be the air filter!
After that, I've been able to richen my '85 S2 up enough to run better by turning (you need a very long 3mm allen wrench...or long skinny hands)the hex head screw on the side of the MAF sensor...
I might be wrong, but try turning it counter-clockwise in 1/2 turn increments and see if it makes a difference.
Normy
After that, I've been able to richen my '85 S2 up enough to run better by turning (you need a very long 3mm allen wrench...or long skinny hands)the hex head screw on the side of the MAF sensor...
I might be wrong, but try turning it counter-clockwise in 1/2 turn increments and see if it makes a difference.
Normy
02-19-2002, 12:23 PM
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This is almost certainly a leaky injector or two.
You don't have a cold start injector. The warmup enrichment is done through wider injector pulses.
Bosch injectors are sensitive to being left sitting around unused. I sent all 8 928 injectors out to be balanced and cleaned and with only 35K miles on them, several were dripping and they all had varying degrees of lousy spray pattern. My 944, which has well over 100K miles, had nearly perfect injectors (no leaks, good spray pattern).
Anyhow, your description is exactly what leaking injectors cause. Or a failed fuel pressure regulator but you said your fuel pressure is correct, so that leaves us the injectors.
The good news is that there are services around that can restore your injectors to their original flow rate and spray pattern, and you probably won't have to replace any - or maybe one or two at the most. As opposed to all 8.
I know shops here in the US that perform this...they must exist in the UK too.
Bryan
You don't have a cold start injector. The warmup enrichment is done through wider injector pulses.
Bosch injectors are sensitive to being left sitting around unused. I sent all 8 928 injectors out to be balanced and cleaned and with only 35K miles on them, several were dripping and they all had varying degrees of lousy spray pattern. My 944, which has well over 100K miles, had nearly perfect injectors (no leaks, good spray pattern).
Anyhow, your description is exactly what leaking injectors cause. Or a failed fuel pressure regulator but you said your fuel pressure is correct, so that leaves us the injectors.
The good news is that there are services around that can restore your injectors to their original flow rate and spray pattern, and you probably won't have to replace any - or maybe one or two at the most. As opposed to all 8.
I know shops here in the US that perform this...they must exist in the UK too.
Bryan
02-19-2002, 12:39 PM
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hi bryan
thanks for the information. i guess a leaky injector passes fuel all the time?
the car has been in storage for four years! so i guess that would be enough to upset such a precision device.
is it possible to pull each injector one at a time and observe the spray pattern....i appreciate that high pressure fuel sprays and a running engine are a tad dangerous! maybe i could fabricate a pulse generator and drive the injectors away from the car.
anyway, i will attempt to find an injector restorer here in the UK.
regards
john
thanks for the information. i guess a leaky injector passes fuel all the time?
the car has been in storage for four years! so i guess that would be enough to upset such a precision device.
is it possible to pull each injector one at a time and observe the spray pattern....i appreciate that high pressure fuel sprays and a running engine are a tad dangerous! maybe i could fabricate a pulse generator and drive the injectors away from the car.
anyway, i will attempt to find an injector restorer here in the UK.
regards
john
02-19-2002, 02:29 PM
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John,
Have you checked out Temp sensor 2 at the front of the engine ? If it or its connections are open circuit, the injector pulses will be set to maximum.
John
Have you checked out Temp sensor 2 at the front of the engine ? If it or its connections are open circuit, the injector pulses will be set to maximum.
John
02-19-2002, 02:59 PM
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John,
I recommend going down to the "Rough Running" posts. With the car sitting up that long, even after cleaning the injectors, you will probably continue to have problems from crap in you lines. I was in the same boat of having my car sit up for years.
The very first thing I would try would be the system self clean up process;
1)dropping the gas tank to less than 1/2 full, 2)disconnect the computer
3)add three cans of Berryman injector cleaner 4)hook up a battery charger,
5) jumper the fuel pump relay and recirculate the gasoline in the fuel loop for several hours through the filter to clean out the lines.
Then hook everything back up as normal and allow the engine to idle for an half hour to hopefully clean the injectors.
If it is still running real rough...send the injectors out to be cleaned and tested. If it is running just a little rough drive it to hopefully clean out the rest. You may get lucky and the problem ends up fixed, saving a bunch of money.........it is worth a try
Don't forget to replace the fuel filter when you finish and add a can of injector cleaner with every tank until no sign of the rough running returns.
Take two asprins and call me in the morning <img src="graemlins/wave.gif" border="0" alt="[byebye]" />
hawke <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
I recommend going down to the "Rough Running" posts. With the car sitting up that long, even after cleaning the injectors, you will probably continue to have problems from crap in you lines. I was in the same boat of having my car sit up for years.
The very first thing I would try would be the system self clean up process;
1)dropping the gas tank to less than 1/2 full, 2)disconnect the computer
3)add three cans of Berryman injector cleaner 4)hook up a battery charger,
5) jumper the fuel pump relay and recirculate the gasoline in the fuel loop for several hours through the filter to clean out the lines.
Then hook everything back up as normal and allow the engine to idle for an half hour to hopefully clean the injectors.
If it is still running real rough...send the injectors out to be cleaned and tested. If it is running just a little rough drive it to hopefully clean out the rest. You may get lucky and the problem ends up fixed, saving a bunch of money.........it is worth a try
Don't forget to replace the fuel filter when you finish and add a can of injector cleaner with every tank until no sign of the rough running returns.
Take two asprins and call me in the morning <img src="graemlins/wave.gif" border="0" alt="[byebye]" />
hawke <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
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02-19-2002, 04:29 PM
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Wow, this thing was sitting for 4 years? Definitely check the injectors. An injector won't spray fuel at full blast when it's bad, but it'll drip.
You can't pull the injector one at a time to check, you have to pull all 4 from one bank and check them all together. Each injector has a little hold-down and then you will probably have to struggle to pull them out of the manifold runners. They like to stick in place. Once one set of 4 is out, bring the fuel system up to pressure (jumper the fuel pump relay socket appropriately until the system is at full pressure) and check for dripping injectors. Repeat on the other side.
Once you have an idea what shape your injectors are in, then we can proceed. You should have at least one really leaky, drippy injector to get the symptoms you describe. If none leak, then I'd put off getting them cleaned and balanced until you've got the car in solid running shape. And we'll have to look elsewhere for the problem.
The suggestion about the temp sender is also excellent. Definitely check that as well if it's not the one you've checked already.
Bryan
You can't pull the injector one at a time to check, you have to pull all 4 from one bank and check them all together. Each injector has a little hold-down and then you will probably have to struggle to pull them out of the manifold runners. They like to stick in place. Once one set of 4 is out, bring the fuel system up to pressure (jumper the fuel pump relay socket appropriately until the system is at full pressure) and check for dripping injectors. Repeat on the other side.
Once you have an idea what shape your injectors are in, then we can proceed. You should have at least one really leaky, drippy injector to get the symptoms you describe. If none leak, then I'd put off getting them cleaned and balanced until you've got the car in solid running shape. And we'll have to look elsewhere for the problem.
The suggestion about the temp sender is also excellent. Definitely check that as well if it's not the one you've checked already.
Bryan
02-19-2002, 09:40 PM
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Find the leaking injector by looking at the spark plugs. The rich/leaking/dripping injector is the one over the sooty black plug.
If the injector really is leaking, you'll see the fuel pressure bleed down shortly after the engine is shut down. At that time, the plug under the leaker will be wet as well as sooty.
There may be more than one leaking through, by the way.
If you do decide to try and test the spray pattern, be aware that the coil in the injector only neads about 9 volts to actuate. If you apply 12 volts as one might assume to be needed, you will toast the little coil in short order. Chances are pretty good the the replacement injectors you would need would flow and shut off just fine.
Another warning: If you do have a leaking injector, don't even think of doing the "fuel pump relay jumpered" trick for flushing the fuel lines and rails. The fuel will continue to leak into the manifold and the chamber, causing a hydraulic lock on attempted restart, or a fire. No matter which, the oil in the crankcase will be diluted just a bit from all the fuel pouring in.
So, not a bad idea to get some fresh oil in there after this ordeal is over.
Cheers! <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
If the injector really is leaking, you'll see the fuel pressure bleed down shortly after the engine is shut down. At that time, the plug under the leaker will be wet as well as sooty.
There may be more than one leaking through, by the way.
If you do decide to try and test the spray pattern, be aware that the coil in the injector only neads about 9 volts to actuate. If you apply 12 volts as one might assume to be needed, you will toast the little coil in short order. Chances are pretty good the the replacement injectors you would need would flow and shut off just fine.
Another warning: If you do have a leaking injector, don't even think of doing the "fuel pump relay jumpered" trick for flushing the fuel lines and rails. The fuel will continue to leak into the manifold and the chamber, causing a hydraulic lock on attempted restart, or a fire. No matter which, the oil in the crankcase will be diluted just a bit from all the fuel pouring in.
So, not a bad idea to get some fresh oil in there after this ordeal is over.
Cheers! <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
02-19-2002, 10:16 PM
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John B:
Does your motor oil have a strong gasoline smell?
Dr. Bob:
Two injectors on my car were leaking, but the spark plugs (3k miles old) looked all similar. There was no difference whatsoever between the spark plugs.
Only the flow tests before cleaning revealed that injector 7 and 8 were leaking, and most likely causing the gasoline smell in the almost new (1k miles) motor oil.
The injectors were done by Cruzin Performance at <a href="http://www.cruzinperformance.com/" target="_blank">http://www.cruzinperformance.com/</a> and are now within 2% of specs. Including express shipping, this cost little over $100. Mike Schmidt has successfully used their services and recommended them.
Does your motor oil have a strong gasoline smell?
Dr. Bob:
Two injectors on my car were leaking, but the spark plugs (3k miles old) looked all similar. There was no difference whatsoever between the spark plugs.
Only the flow tests before cleaning revealed that injector 7 and 8 were leaking, and most likely causing the gasoline smell in the almost new (1k miles) motor oil.
The injectors were done by Cruzin Performance at <a href="http://www.cruzinperformance.com/" target="_blank">http://www.cruzinperformance.com/</a> and are now within 2% of specs. Including express shipping, this cost little over $100. Mike Schmidt has successfully used their services and recommended them.
02-19-2002, 11:31 PM
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I have an 82 s and I think that I have narrowed down the problem of not running to the fuel injectors all being plugged up. The car has been sitting for 7 years and I have done everything to come to this conclusion. The car runs on starting fluid. I have cleaned all of the fuel system, checked the computer, replaced temp sensor, replaced relays, checked fuel pressure, checked to see if the injectors are firing, listened to the injectors to see if they are firing and just about everything else. Nichole. I am so glad that you mentioned Cruzin Performance. I am calling tommorow and having the injectors cleaned and even replaced to bring them all into tollerance. I will let all of you know how this pans out.
02-19-2002, 11:37 PM
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johnb,
Dr. Bob is absolutely correct about the potential problem of the cylinder flooding from a leaking injector when using the approach I describe above. Jumping the pump relay and cleaning in place without the engine running could cause a problem. <img src="graemlins/c.gif" border="0" alt="[ouch]" /> Simply try clean up the injectors by allowing the engine to idle with a heavy does of cleaner in the tank .
Thanks dr. Bob................
Dr. Bob is absolutely correct about the potential problem of the cylinder flooding from a leaking injector when using the approach I describe above.
Jumping the pump relay and cleaning in place without the engine running could cause a problem. <img src="graemlins/c.gif" border="0" alt="[ouch]" /> Simply try clean up the injectors by allowing the engine to idle with a heavy does of cleaner in the tank .Thanks dr. Bob................
02-20-2002, 03:20 AM
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Nicole wrote:
>> Dr. Bob:
>>
>> Two injectors on my car were leaking, but
>> the spark plugs (3k miles old) looked all
>> similar. There was no difference whatsoever
>> between the spark plugs.
>>
>> Only the flow tests before cleaning revealed
>> that injector 7 and 8 were leaking, and most
>> likely causing the gasoline smell in the
>> almost new (1k miles) motor oil.
I think that the magnitude of the leak John was describing, with smoke and soot from the exhaust, points to a pretty big leakthrough problam. That much soot in the pipes would show up on a plug for sure.
Meanwhile, your car was probably just dribbling a little, well within the range of the oxygen sensor and the feedback loop to clear up.
I'm also impressed that you discovered and cured the problem. I guess I need to spend a few more minutes sniffing the oil when I check the level. One more task to add to the list...
<img src="graemlins/yltype.gif" border="0" alt="[typing]" />
>> Dr. Bob:
>>
>> Two injectors on my car were leaking, but
>> the spark plugs (3k miles old) looked all
>> similar. There was no difference whatsoever
>> between the spark plugs.
>>
>> Only the flow tests before cleaning revealed
>> that injector 7 and 8 were leaking, and most
>> likely causing the gasoline smell in the
>> almost new (1k miles) motor oil.
I think that the magnitude of the leak John was describing, with smoke and soot from the exhaust, points to a pretty big leakthrough problam. That much soot in the pipes would show up on a plug for sure.
Meanwhile, your car was probably just dribbling a little, well within the range of the oxygen sensor and the feedback loop to clear up.
I'm also impressed that you discovered and cured the problem. I guess I need to spend a few more minutes sniffing the oil when I check the level. One more task to add to the list...
<img src="graemlins/yltype.gif" border="0" alt="[typing]" />
02-20-2002, 04:18 AM
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Dr. Bob:
I had a little help from some wonderful members of this board, and a great local "teacher". This actually came out in the search for a different problem (rough idle), which unfortunately has not been cured by the cleaned injectors.
I'm progressing in my apprenticeship as a 928 mechanic...
I had a little help from some wonderful members of this board, and a great local "teacher". This actually came out in the search for a different problem (rough idle), which unfortunately has not been cured by the cleaned injectors.
I'm progressing in my apprenticeship as a 928 mechanic...
02-20-2002, 05:24 AM
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wow........what a response, thanks guys.
BTW my car does not have oxygen sensors...just plain old LH Jetronic.
i have found a company here in the UK, that will ultrasonically clean, rejet, refilter and calibrate the fuel injectors...for the princely sum of £15 each. so the next task is to pull all the injectors and pack them off for some TLC. hopefully this will go some way to restoring full operation.........aren't 928's fun?
regards to all.........johnb
BTW my car does not have oxygen sensors...just plain old LH Jetronic.
i have found a company here in the UK, that will ultrasonically clean, rejet, refilter and calibrate the fuel injectors...for the princely sum of £15 each. so the next task is to pull all the injectors and pack them off for some TLC. hopefully this will go some way to restoring full operation.........aren't 928's fun?
regards to all.........johnb