Missing Cylinder - 3.2 Carrera - Likely Fuel Injector - Replace?

[Franks89-911]

I have a missing cylinder. I have ruled out plugs, cap, rotor, & wires. Suspect it is a fuel injector.

Our host does not carry replacements? https://www.pelicanparts.com/More_Info/93060612000.htm?pn=930-606-120-00-OEM&bc=c&SVSVSI=0603

So I found these...but my sus meter is going off. Only $34 per? https://www.carparts.com/details/Porsche/911/Replacement/Fuel_Injector/1988/Carrera/6_Cyl_3-dot-2L/REPP314301.html

I sure would like to replace all 6 of these though.

Also, anyone have a walk-thru of the remove & replace procedure?

[PeteKz]

Lots of missing info (not to mention missing a cylinder ).

Why do you think it's a fuel injector? What tests have you run? How did you rule out the ignition system? Have you swapped fuel injectors to see if the problem follows the injector or stays with the cylinder?

Next, please put your mileage in your signature line too.

[almostordinary]

Copy what Pete said.

I just bought these for my 87 3.2
https://www.ebay.com/itm/372467329781

[Franks89-911]

Originally Posted by PeteKz

Lots of missing info (not to mention missing a cylinder ). Why do you think it's a fuel injector? What tests have you run? How did you rule out the ignition system?

Next, please put your mileage in your signature line too.

___________________________________
Addl info:

-Yes, a 'misfiring' cylinder.
-78k miles.
-Recently replaced all 6 plugs as part of regular tuneup/valve adjust procedure. But to be sure I put in the old plugs that I knew worked, same symptom.
-Checked all SP wires for resistance. (replaced those at 68k, < 9 years old Beru, no physical damage to them, all snug on plug and dist cap ends)
-Replaced dist cap and rotor.
-Car had not been started in a couple of months.

[PeteKz]

Better. Does it miss just at idle, or at full throttle? If only at idle, pour a bottle of Techron Concentrate in the tank and go drive the piss out of it. If the miss is still there, then swap injectors and see if the problem follows the injector. If so, you've isolated it. Two options: have old injectors cleaned and tested. Some NAPA stores offer this service, and probably others in your area. Second option, new injector. At only 78Kmi, I doubt you need a full set of injectors.

Also, is this a new problem, or did it exist before the car sat for several months?

Troubleshoot first, then only change one thing at a time. Don't throw parts at the problem. That will only waste money and introduce new variables.

[dg567]

2nd on the Techron - if that doesn’t help, you can pull all 6 and get them cleaned/flow tested.

[fallingat120mph]

I have switched from Techron to BG 44k and had great results on all my 20-40 year old cars. Still use Techron in my motorcycles. All cars and bikes have high mileage and original injectors, etc...

The 44k and a few days of really getting on it (in my 86 911) seemed to make a difference.

[Franks89-911]

Originally Posted by PeteKz

Better. Does it miss just at idle, or at full throttle? If only at idle, pour a bottle of Techron Concentrate in the tank and go drive the piss out of it. If the miss is still there, then swap injectors and see if the problem follows the injector. If so, you've isolated it. Two options: have old injectors cleaned and tested. Some NAPA stores offer this service, and probably others in your area. Second option, new injector. At only 78Kmi, I doubt you need a full set of injectors.

Also, is this a new problem, or did it exist before the car sat for several months?

Troubleshoot first, then only change one thing at a time. Don't throw parts at the problem. That will only waste money and introduce new variables.

——————————
Great advice thx. Most noticeable at idle. At 3k+ rpm seems to smooth out a bit. Idle is also high, around 1200 now vs normal which for me is 800-900. There is some smoke in exhaust too.

I’m a bit afraid to drive it with a misfiring cylinder but will add the Techron and see. This is a New problem - just happened when I started it up this weekend. Before then, she ran like a top. New plugs and a good valve adjust had her purring.

[john walker's workshop]

Might be a sucked in intake gasket. Happens a lot. Gotta pull the intake on that side to find out.

[proporsche]

do you know which cylinder?? by disconnecting one spark plug at a time...after spray around that cylinder car cleaner and see.Most likely as John W. said ...could be your problem since even the idle is higher...

Ivan

[Franks89-911]

Originally Posted by john walker's workshop

Might be a sucked in intake gasket. Happens a lot. Gotta pull the intake on that side to find out.

Hi John

Thx for the reply

Are you talking about these little $1 gaskets? https://www.************.com/Porsche-911Carrera-1989_p-4434-intake-manifold-gasket-32l.aspx

Looks like the same material as the valve cover gaskets. So those can break apart and get sucked into the engine?

Now I'm *really* afraid to drive it anywhere. Someone else here said "drive the piss out of it" but if it's this gasket vs. a fuel injector, wouldn't that be a real risk?

Removing the intake manifold is beyond this noob's comfort level for sure. I'm likely headed to Goldcrest Motorsports. Sincerely appreciate the help tho.

[john walker's workshop]

They get hard and crack and if the intake bolts are a bit loose, like most of them, get sucked in, and the air leak kills cylinder performance at idle and real low RPM. There is a plastic spacer with a gasket on top and bottom.

[john walker's workshop]

Old post that relates. Dead cylinder number 1 Pic on post 31.

[john walker's workshop]

Another pic.

[mziggy16]

I had similar issues this summer after doing the clutch and all of the ‘while you’re in there” items.

Initially I had a really rough idle and it would die. That was a vacuum leak that we diagnosed and remedied.

Then, I had a boggy first gear and a verrry mild stumble around 2k RPM’s. After all the DIY troubleshooting I could do at home I had the dealer diagnose a dead injector. Their reco was to ship it out for a rebuilt injector at a shop in CA. Unfortunately I don’t have the shop name but the forum can likely help with that. The dealer was adamant that this was the only option that they would endorse because of unavailable Porsche-spec parts.

[Nick Triesch]

Just had this happen to me . Took to shop because of bad mis and idle . Shop found bad sucked gasket on drivers intake. One gasket was installed 8000 miles ago up side down by Porsche shop. During top end. Repaired and mis and idle went back to normal . Repair was just over $1000 for that repair.