Running rich, bad fuel injectors?

DW5.0L · Mar 19, 2006

I recently started my rebuilt engine and have it just about dialed in. Found a few vacuum leaks and that the plugs were not gapped right. Fixed those, but I still am getting a black sooty residue out of the exhaust and the brand new plugs were covered with soot. My builder cleaned the fuel injectors and I reused them. But they are the original ones, so a new set of 19's are coming soon.

Anybody have any other suggestions why it would run this way? Otherwise the engine performs good, no knocking or missing and idles failry good. A new TPS was added and set properly. Everything else is new except for the injectors. I also removed all of the smog accessories. When I checked the running vacuum it was only at 13 at idle, so I think I still have another leak somewhere.

Help!

craigwhite89gt · Mar 19, 2006

hmmm.. If the injectors were old more than likley they would be clogging up and running lean. Sounds to me like maybe you have a weak ignition.

90mustangGT · Mar 19, 2006

Black soot? Sounds like oil, such as a bad valve guide or seal. Usually, rich fuel is a blueish smoke, and will foul a plug and it will be brown, but black soot? What plug(s) does it do this in.

Daggar · Mar 19, 2006

Hahaha... it just occured to me that those injectors that you're talking about getting rid of are probably the ONLY part that you can really trust. It's everything ELSE that's new and unproven.

DW5.0L · Mar 19, 2006

The injectors while possibly reliable, are definitely well proven with 197,000 trouble free miles. Thats alot of years and miles.

Seems to dumping too much fuel. Motorcraft plugs.

craigwhite89gt · Mar 19, 2006

when mine was "dumping fuel" mine had a white smike out the pipes and would about knock you out from gas smell. id say go run it around for a little while to get a good feel for it. Cuz if your running too rich at lower rpms it will stutter. Go run it around if u can and see what the car does come back and pull a plug out and see what it looks like. And get on it a little.

HISSIN50 · Mar 19, 2006

I just woke up and likely missed it - Is your '88 SD? If it is, running 13" of baseline vac is not gonna play real nice with the puter (it should run rich).

Good luck.

DW5.0L · Mar 19, 2006

Yep its a SD car. I'll need luck, thanks.
What is the normal running vacuum?

HISSIN50 · Mar 19, 2006

DW5.0L said:
Yep its a SD car. I'll need luck, thanks.
What is the normal running vacuum?

A stockish SD car sees 18-20" hg at idle. You can see that you are runnin at 2/3 of that.

jrichker · Mar 19, 2006

The fuel pressure regulator may have failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

Try cleaning the MAF. To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.

Pokageek · Mar 19, 2006

The 94/95's are a little bit different but my car was doing this and turned out to be the coolant tempurature sensor. I didn't mind replacing it as it was 12 years old anyway and a $21 part.

DW5.0L · Mar 19, 2006

Wow, I do have a vacuum problem for sure, if thats whats normal. I'll have to try to pull the codes. Thanks for links and tips.

DW5.0L · Mar 21, 2006

what is the normal fuel pressure psi on an 88 SD car?

HISSIN50 · Mar 22, 2006

DW5.0L said:
what is the normal fuel pressure psi on an 88 SD car?

30 PSIG or above at idle with the vac line attached, and at simulated WOT, look for 30-38 PSI.

DW5.0L · Mar 24, 2006

Thanks. I went ahead and ordered a FRPP 19lb set and new FPR. Now I'll just have to find and fix the vacuum leak(s).

DW5.0L · Apr 4, 2006

Running better, but.....

I replaced the fuel injectors and FPR and drove the car for the first time for 7 miles. It does idle better now, but its still rich. The temperature is low and maybe that has something to do with the richness. So I am going to install a new ECT sensor to see if that will help.

DW5.0L · Apr 4, 2006

The car still is not running right. I changed the oil and noticed it had a strong fuel odor to it. I just don't know what the problem is at this point.

HISSIN50 · Apr 4, 2006

I know how it is to get wrapped-up and get a little tunnel vision perhaps. Did you figure out the vac reading issue? 13" at idle, on a SD puter, will probably run on the rich side.

Good luck.

DW5.0L · Apr 15, 2006

Did a compression check and found out the following:

Cylinder 1-158 Cylinder 5-158
Cylinder 2-155 Cylinder 6-153*the lowest
Cylinder 3-158 Cylinder 7-158
Cylinder 4-158 Cylinder 8-156

Going to change out the plugs as the are still sooty and now have a light coat of oil. The rebuilt engine only has 20 miles on it since the first start up. Also have to check the vacuum and test the EGR. Either one of those could be making it run rich. Will see what happens, but at least I know the engine is not toast.

DW5.0L · Apr 15, 2006

Vacuum still sucks.....

Its still 13 at vacuum and only 23 at WOT. Blocked off EGR to see if that would help and it was the same readings.

Not sure what direction to go in now.

Running rich, bad fuel injectors?

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