dogleg

hi im new on here i,ve got an 81 928 german import to ireland.i have a running problem mostly when the car is warming up from cold.the car starts easily from stone cold and idles at 1500 but will not rev at this point without pumping the trottle and playing with it.making the car undriveable untill its warmed up a lot,after 10 mins idle speed will have dropped to 800 rpm and car can be driven fairly normally although not running cleanly untill revs climb past 2000 rpms even when fully up to temp, i have put new fuel filter, air filter, plugs, and ht leads on recently trying to sort this annoying fault.my next step is to fit new injectors anyone had a similiar fault?will the injectors sort this?

Rod Underwood

I had a similar problem with an 87 that sat in the garage all winter. I ran it down to 1/4 tank and added two bottles of Tecron injector cleaner and drove it about 20 miles. Too care of it completely.

Don't know if this is your problem, but it's a cheap try.

Good luck
Rod

dogleg

thanks rod might try this before i fit new injectors

James Bailey

Whoa there this is a CIS car, the injectors just spray all the time ! You need to read up on how CIS works especially the warmup/control pressure regulator. That is what controls the mixture,adds fuel when the engine is cold to keep it running etc. Your injectors are probably O K . The 78-79 USA cars use the same system and MUCH has been written here about getting them to run correctly. You have already replaced unneeded parts.

dogleg

i have read up on the system.the parts i replaced all needed changing plugs old and worn, leads no omhs reading on most of them,wheres the harm in fitting a new fuel and air filter?dont thing it could be the warm up reg as it doesnt run well low down even when hot!couldnt the injectors be blocked or worn giving a bad spray pattern at low rpms even though the run all the time everythings 30 years old?

michael j wright

If the injectors were bad you most likely woudn't be starting fine and running smooth for the first ten min's or so. I would first do all the basics, check for vac leaks, check system preasure-both cold and warm, check idle air bypass for proper opperation. Last but not least no matter how much you've "read up" on this sytem- untill you really really understand how it works together-listen to what those here on the list tell you-most of all Mr. Bailey. P.S. welcome to the list. :-)

dogleg

cheers for welcome ive just had a smoke test on the inlet system checking for leaks all clear im working my way through all that been suggested

Dennis Wilson

Try cleaning the injectors like previously mentioned. If some are partially plugged in the open position, it could cause your problems. Also check the warm up regulator and auxillary air valve for shorts to ground or open circuits on their heaters and check to make sure they are getting 12 volts when the engine is running.

If the car has sat idle for a while, the piston in the fuel distributor could be gummed up and cause you rough running problem especially at the higher rpms.

Dennis

dogleg

not sure its even worth cleaning the injectors there $27 each new and not the easiest to remove and install,think to get them checked and cleaned is a specialist job!it runs sweat as a nut in the high rpms silky smooth and loads of horse power so hopefully not a problem with the fuel distributer,will check other areas you have mentioned.thanks

Mike Simard

If this is a CIS car than doesn't this problem sound like the little aux injector at the front of the intake and/or the sensor that controls it?

Brett928S2

Hi

Change the Distributor cap and rotor arm ... and I dont mean check them lol...change them...you did well to change all the other electrical parts, and although the cap/arm may not be the cause of the problem, it wont harm anything to change them (as they are probably YEARS old) and it may well help

On the fuel side, I am not sure if you can get it in Ireland, but if you can try some FORTE INJECTION CLEANER (usually trade only in garages but you could try Ebay)... 2 cans to one tank of fuel...

Its the best you can get to clean injectors apart from removing them...

All the best Brett

dogleg

tried 2 cans of injector cleaner and filled the tank a few days ago but no improvement.this car would be glorious if i could get it to run right cheers brett

Landseer

CIS fuel system aside (for which there are specific tests), I'm wondering if you have a vac leak despite the smoke test.

Unless you know that its already been done, a good early step in refurbishment is replacement, of the rubber hoses attaching to the base of the throttle body and the spider boots.

Welcome and good luck with your new shark!!!

I really like the early style ones.

A good set of engine bay pictures might help, especially with some closeups.

LT Texan

Welcome to the list!

I fumbled around in the dark, spending money and never understanding what was wrong with my CIS until I bought CIS Fuel Pressure Gauges and Ben Watson's book to learn how to use them.

Good luck!!!

dogleg

may well invest in said book before too long!also had it on a diagnostic lap top with exhaust pulse it detected miss an every other cylinder ie 2 4 5 and 7 friend of mine checking it.he seem to think injectors at the end of that test also.