cold start system LH Jetronic
02-20-2002, 11:14 AM
#16
Burning Brakes
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A couple quick points to hopefully minimize confusion about this thread:
Johnb's car has LH-Jet, meaning pulsed injectors. Euro cars '83 and earlier had CIS, which have their own set of injector issues. Having the L-Jet and LH-Jet, or pulsed, Bosch injectors cleaned can be done reasonably. Cleaning the CIS injectors is very difficult or impossible I've heard, although ultrasonic baths and the like have been known to improve their performance.
Johnb's car also has no O2 sensor/closed loop mixture control so it's extra sensitive to air mass meter problems (see separate thread) and won't try to alter the mixture - it'll just run rich or lean until you tune/repair it properly.
Johnb - it sounds like you found a shop that'll service the injectors properly. Make sure you get new O-rings for the injectors, and the little "hat" shaped pieces at the tip replaced too - some will be cracked and all will be nasty. This is usually included in the service.
Also, the fun ain't over yet. Removing the injectors from the fuel rail will require you to destroy the little ~5cm segment of fuel line going from the rail to each injector. Just cut it apart and don't worry about it. You'll want to replace this fuel line. The 928 specialists here in the US sell kits containing new fuel line segments and the little fittings at each end. US suppliers will ship to the UK no problem if you can't find these kits in the UK. You'll then have to muscle your cleaned injectors onto the new fuel line segments, then muscle that onto the rail. 8 times. It's a pain and takes some patience and muscle and wiggling, but it will go together.
Let us know how it goes.
Bryan
Johnb's car has LH-Jet, meaning pulsed injectors. Euro cars '83 and earlier had CIS, which have their own set of injector issues. Having the L-Jet and LH-Jet, or pulsed, Bosch injectors cleaned can be done reasonably. Cleaning the CIS injectors is very difficult or impossible I've heard, although ultrasonic baths and the like have been known to improve their performance.
Johnb's car also has no O2 sensor/closed loop mixture control so it's extra sensitive to air mass meter problems (see separate thread) and won't try to alter the mixture - it'll just run rich or lean until you tune/repair it properly.
Johnb - it sounds like you found a shop that'll service the injectors properly. Make sure you get new O-rings for the injectors, and the little "hat" shaped pieces at the tip replaced too - some will be cracked and all will be nasty. This is usually included in the service.
Also, the fun ain't over yet. Removing the injectors from the fuel rail will require you to destroy the little ~5cm segment of fuel line going from the rail to each injector. Just cut it apart and don't worry about it. You'll want to replace this fuel line. The 928 specialists here in the US sell kits containing new fuel line segments and the little fittings at each end. US suppliers will ship to the UK no problem if you can't find these kits in the UK. You'll then have to muscle your cleaned injectors onto the new fuel line segments, then muscle that onto the rail. 8 times. It's a pain and takes some patience and muscle and wiggling, but it will go together.
Let us know how it goes.
Bryan
02-20-2002, 12:01 PM
#17
Rennlist Member
Rennlist Site Sponsor
It would be well worth the effort to pull the vacuum lines from the fuel pressure regulators/dampeners and check for any traces of fuel in the vacuum lines. Replace any unit that shows any trace of fuel in its line.
