snoel

1989 944 S2 running a slight spotty at idle. Nothing major, just a blip or skip randomly at idle. I think it might need some injector cleaning. Also, I am changing out the cap, rotor and spark plugs tonight. Should I look to do the coil as well? Thanks.

John_AZ

My '87 decided to do this about 3 weeks ago after years of smooth idle---like yours, just a random bounce. I think the cars can sence lack of attention.

I cleaned my ICV with Gumout Fuel Injector & throttle body cleaner. New hoses and clamps on the ICV. Checked harness electrical connections on the engine harness. Cleaned the TB throttle body with the same Gumout. Charged battery and cleaned grounds and battery connections. Disconnected the O2 sensor to see if it improves the idle "blip". Checked vac lines and other hoses for cracks.

My next steps will be to rebuild the TB with the Arnnworx TB kit-purchased.
Then check the AFM for a dirty track and "barn door" motion.
Then do a DIY clean and reseal the injectors with new injector top filter screens.
I have bought a new fuel pressure damper and may get a new FPR.

My fuel filter is nearly new.

You could try Chevron Super HD injection cleaner in a couple tanks of gas. Use only Premium Plus gas for a couple tanks of gas.

Let me know how you solve yours.....

GL
John

ernie9468

Coil usualy last a long time on 944 ,what you could do is take the cover off check the wires &clean the connections ,sure hope you did get the rigth spark -plugs witch are (Bosche Super Plus oe copper plug).They migth seem cheap compare to to (platinum) but they are the one that will do the best job on your car .Be careful when pulling the spark plugs wires ,pull even & straigth up. I'll give you a hint here ,before installing the new one put a dab of vaseline on the treads then use a piece of rubber hose to tread them in instead of the socket,this way there is less chance of getting them in there cross tread since the are so deep in there.Also while at it it's time to clean the wires off & apply some rubber conditioner on them.I guess for the rest John said it all.

snoel

Thanks for the advice. I don't have the Bosche. I have the Autolite Iridium. What's the difference? Frankly, I don't know what I have in there now. I am on the PO plugs.

John_AZ

Iridium are one of the best to use---some say you will get 1 1/2 HP boost. Not sure about the Autolite brand.

Like ernie, I am using the cheap, copper -----great conductivity------NGK. I was using Bosch cheap copper until the members of Rennlist convinced me to try NGK

One thing I forgot to mention, I read that the DME temp sensor, even if it reads good (resistance) might be the problem per Porsche and many mechanics.

GL
John

ernie9468

[QUOTE=snoel;8020354]Thanks for the advice. I don't have the Bosche. I have the Autolite Iridium.

Hard to say how Autolite will fare, since the majority of 944 owners are using either NKG or Bosche maybe somebody have try Autolite out there & will chip in.

Crimson Nape Racing

IMHO, Seafoam is the best stuff to clean the intake/injectors.

Porsche16V944

ya, i also use seafoam. Worked wondering in my VW through the vacuum lines. I put a bottle in the fuel tank of my 944 so far with no problems