As some of you are aware of, we recently replaced fuel injectors, regulator and FPD due to a couple fuel leaks. While we were in there, we took advice from all of you on the forum and replaced as many vacuum lines as we could along with all the check valves as well as all new solenoids. We don’t want to go back at this again so wanted to end up with basically all new parts in that area. We were extremely careful routing all our lines, checking for tight fits, no crimping, checking and double checking proper placement, etc. We got it all put back together yesterday evening. It started, but it went to 2000 RPM for several seconds before settling into 1000 RPM that were really rough. We also had quite a bit of black smoke coming from the exhaust that we did not have before. It’s rather disappointing, to say the least. The only thing we encountered that raised an eyebrow as we put everything back together was a pin that had come out of the connector to the idle air control valve. We were able to get it to click back in but it was out, so perhaps that could be an issue. We’ve spent a lot of time reading the forum and pouring over the tech manuals we downloaded. Just looking for a good place to start troubleshooting. Any guidance would be greatly appreciated.

 

Sounds like it is running very rich. Are the plug wires OK? Any plug fouling?

 

is the MAP sensor hooked up? fuel temp and coolant temp plugs not swapped?

 

Checked fuel pressure and volume according to service manual and all
is well there. Triple checked connections and they’re all correct according to manual.

Car ran fine prior to us tearing it apart to find and repair the fuel
leak. Just super disappointed that we once again have it all torn apart.

Please keep sending suggestions. Thanks all.

 

Based on what I just encounter about 5 mins ago...

Earlier today I was installing my engine damper, in the process of doing so I removed my Brake booster vac-line to access the mounting point.. But I totally forgot about putting it back.

Well.. Just now I went to start my car, my engine was going crazy RPM was idling at 2000 and keep on bouncing up and down. But after back tracking what I did earlier in the day, I reconnected the hose.
and everything is good now.

So It seem like you're having vacuum leaks issue.
I hope that help.

 

You say you replaced injectors - with stock or aftermarket injectors?

Dale

 

sorry what mods does the engine have? If it has stock ECU check for codes.

 

black smoke and rough idle sounds like a MAP sensor issue, as already mentioned. maybe take another look at that.

 

I had a similar issue and it was an out of spec water temp sensor, the one located on the back of the water pump housing. Could be the sensor or the wiring. If you have a PFC you can see the sensor output somewhere in the commander menu.

 

i've seen people swap the fuel temp and coolant temp plugs, and you get a car that runs like poop, no CEL's...

back in the day, there was a used car that came in for something, and the tech swapped the two plugs, and $12,000 later (engine, turbo, harness, etc etc etc), they hired the local FD guy to come over and swap the plugs the right way round....

 

Replaced with stock injectors from atkins rotary. Did the volume check per service manual and all injectors passed. FYI - The car is all stock.

 

Have you checked all the things suggested?

Dale

 

First, thanks for the input for things to check. Have been working on major house project and needed time to think about engine issue without just recklessly tearing back into the car.

The coolant and temp plugs are not swapped, brake booster line is connected, all connections to UIM look good and double checked the MAP line and looks good there too.

I was going to check for codes, but that was going to require an engine warm up first because the battery had been disconnected. The car started, but stumbled and was belching so much black smoke while parked in the garage (mistake) that we made a rookie mistake and shut the car down. This of course flooded the engine. In the short time car ran, no codes were captured.

We’ve pulled the plugs (new) and found the trailing plugs where wet, but the leading plugs didn’t look wet and all of them smelled of gas. At this point, we will run the flood procedure mentioned on this forum and plan on checking each plug for spark.

We don’t really want to rip engine top back apart without a plan or area to focus on.

My questions are –

1. Can any of the solenoids not operating correctly cause rough idle and richness

2. Can the connections to the Air Control Valve be swapped and if so, would it cause the conditions we’re experiencing.

3. The injectors are new and we tested with all clicking each time they were grounded, fuel rails with injectors installed held pressure and each injector passed the volume test per service manual. Can an injector(s) still be bad (stick open) after the testing? Is there a way to check for a sticking injector without sending off to a specialist?

Our focus right now is on what we touched in order to replace rat’s nest and injectors/fuel related items. I know there’s a possibility of a compromised wire(s) within the harness we touched or bad new parts and at this point want to rule out a mistake by us. Again, thank you for the suggestions and look forward to any additional help the forum can provide.

Also, the car is a 95 100% stock.

 

All I can come up with is a malfunctioning ACV. It could cause it to run rich and emit black smoke.

 

No luck yet. Car is still rough idling and puffing black smoke.

We have checked and re-checked all your suggestions to no avail.

Is it possible one of the new fuel injectors we installed is malfunctioning? Does that happen? Do people have them tested prior to install, even if they're new?

We ran the volume tests and power tests prior to install and all checked good. However, the car just seems to be getting too much fuel.

It's 100% stock. It ran prior to us opening it up to replace leaking injectors/FPD.

We've taken the UIM off twice now to verify vacuum lines, etc.

It's disheartening.

 

i have seen one where the lower injector O ring didn't seat right and it had a weird vacuum/fuel leak and ran badly, it didn't pass the leak test though

the other thing, is that the coolant temp sensor and fuel temp sensor have the same connector and if they are plugged in backwards, it runs like you say...

i know of two dealerships back in the day that spent $12k on engines and ecus and turbos because that was plugged in wrong...

 

If one of the injector O-rings are pinched or damaged it can squirt pressurized fuel around the injector and it will dribble down into the engine. You can unbolt the rails and lift them up and pressurize the fuel system to see if any fuel is leaking around an injector.

Dale

 

Wow! Wouldn’t that suck? 😏

We checked those connectors once; but aren’t above looking at them again. Thanks much! And we will definitely be pulling the injector rack out again, so we’ll check those o-rings too.

appreciate the input!

 

Thanks Dale. We’ll definitely check that out when we pull the rack, again. We also found your post on troubleshooting the fuel system. We have a node tester coming tomorrow; so we can run that check too. Appreciate the info!

 

Just wanted to double check, you didn't happen to replace the little filter on the MAP vacuum line with a check valve right? And you do have the filter in the correct orientation?

 

hey! Thanks for the suggestion. We did not replace it but we did go down and double check it tonight to make sure it’s oriented properly.

Thank you!!

 

hi mate I’m getting the same symptoms black smoke on idle I actually removed the map filter then problem started a week later so I put another on if I put it on upside down could it cause the black smoke sometimes white smoke to

 

Have you checked your TPS sensor? I know its a shot in the dark but if that was accidentally bumped during the removal and re-installing of the manifold can cause poor or undesired idle, I believe this is something worth checking to rule out. If you have a PFC you can check the sensor voltage and see if its in proper range/spec.