Progress Thread 93 lx fix'n it up

[diesel farmer]

Back to working on the 93 LX 5.0. A9L ECU came back from ECU Exchange with a # of fixes. The car now starts - that's a plus.

However, now to figure out the seriously rough ide. Assume almost all sensors are original from 1993. At cold start it idles up to 2k to 2,500 RPM and then will drop down and want to die, but I can keep it running with a little throttle. When it warms up it runs a little better, but still very much way off. The ignition timing isn't too far off spec. EGR system is completely unhooked for now (it's missing most of the equipment to make it function). I installed a new IAC.

KOEO - codes 31, 81, 82 and 85 - I think most of these are smog related.

KOER - codes 13, 21, 31, 41 and 91.

I'm "planning" to get a new Motorcraft ECT sensor and O2 sensors.

I have a 70 MM MAF from a 94 Mustang (in what appears to be good condition) I was going to use when upgrading the intake. It's hard to keep the car running and unless I get a helper, I can't check the MAF with it running. Rather than buy a MAF for the stock 5.0, will it help or hurt to try the 70MM MAF? I wanted to get the car running decent before doing the intake related upgrades.

Also wonder if there is an injector issue - see the picture with the one different color injector - so someone has changed out at least one injector.

I know this is a mess -- where is the best place to trouble shoot first? Yes, I have reviewed a number of posts and am getting dizzy reading!! Thanks for suggestions.

 

[diesel farmer]

Went ahead and installed the 70mm MAF. Car runs better but still has a high idle above 1,000 rpm. When I unhook the MAF it does barely idle.

Since I don’t know what it has for injectors, might just swap in the explorer intake and make the intended upgrades.

 

[General karthief]

I see 19 lb injectors, anything else is a mystery, have you gone through the 'surging idle checklist '?

 

[diesel farmer]

I have gone through part of the surging idle checklist and it has helped narrow down the problems. I can get it running decent once it's warm, but at start up it's still running rough. I'm thinking of going ahead and pulling the stock intake and starting from scratch with new sensors and hoses when installing the explorer intake.

There also might still be some wiring gremlins to work out - it's a mystery for sure. As an example, when I wiggle the connector that leads to the TPS it will cause the engine rpm to surge and that shouldn't occur.

 

[Mustang5L5]

There also might still be some wiring gremlins to work out - it's a mystery for sure. As an example, when I wiggle the connector that leads to the TPS it will cause the engine rpm to surge and that shouldn't occur.

That shouldn't happen at all. None of those codes would really cause the car to run too rough. They are EGR codes, charcoal canister, the air pump and a code typical of a clogged (or removed) crossover tube. Code 13 is high idle, but you know this.

You may want to run the cylinder balance test as part of the code reading process. This will help identify if you have a misfiring cylinder. It may not run if the idle is uncontrollable.

You might need to resort to old-school methods here. Laser temp on the headers, wiggle testing. I would even smoke test the car to look for vac leaks.

 

[diesel farmer]

That shouldn't happen at all. None of those codes would really cause the car to run too rough. They are EGR codes, charcoal canister, the air pump and a code typical of a clogged (or removed) crossover tube. Code 13 is high idle, but you know this.

You may want to run the cylinder balance test as part of the code reading process. This will help identify if you have a misfiring cylinder. It may not run if the idle is uncontrollable.

You might need to resort to old-school methods here. Laser temp on the headers, wiggle testing. I would even smoke test the car to look for vac leaks.

I checked for vacuum leaks a couple weeks ago and didn't find any, but will test again to confirm there are no vacuum leaks. I will also warm it up and see what readings I get on the header temperatures.

The below italics text is from a post from [B]jrichker[/B] on July 4, 2020 -- I will give the cylinder balance test a try, but since I have not been able to get it to idle below 900 RPM even when it's warmed up (unless I unhook the MAF, then it will idle low), I'm not sure the balance text will work until I fix the codes.

Trying to to a cylinder balance with active fault codes is a guaranteed way to get bad results. Fix the fault codes BEFORE running a cylinder balance test.

if the engine will not idle at 650-725 under computer control, the cylinder balance will fail with random results. You cannot just screw the throttle stop in or out to get the engine in the desired RPM range. Fix any idle related problems before trying to run the cylinder balance test.

 

[Mustang5L5]

I had a feeling that would the case.

I do suspect a misfire here. Might be wiring related, or other.

 

[Willybill32]

I checked for vacuum leaks a couple weeks ago and didn't find any, but will test again to confirm there are no vacuum leaks. I will also warm it up and see what readings I get on the header temperatures.

The below italics text is from a post from [B]jrichker[/B] on July 4, 2020 -- I will give the cylinder balance test a try, but since I have not been able to get it to idle below 900 RPM even when it's warmed up (unless I unhook the MAF, then it will idle low), I'm not sure the balance text will work until I fix the codes.

Trying to to a cylinder balance with active fault codes is a guaranteed way to get bad results. Fix the fault codes BEFORE running a cylinder balance test.

if the engine will not idle at 650-725 under computer control, the cylinder balance will fail with random results. You cannot just screw the throttle stop in or out to get the engine in the desired RPM range. Fix any idle related problems before trying to run the cylinder balance test.

Gee, I didn’t have an idle problem until I read your quote from @jrichker. Mine idles at about 850.

 

[Mustang5L5]

To answer your question, the 70mm SN95 MAF, 19# injectors and A9L will work fine. It's what i ran on my car and it ran perfectly.

 

[Kid wita 5oh]

when I wiggle the connector that leads to the TPS it will cause the engine rpm to surge and that shouldn't occur.

I'd be replacing the TPS and checking the pins on the harness side

 

[diesel farmer]

I'd be replacing the TPS and checking the pins on the harness side

I will check the TPS and wiring/pins.

I also just fabricated a smoke machine out of pvc/wick/wire and am going to double check for vacuum leaks one of these evenings.

 

[diesel farmer]

I found a vacuum leak with the fabricated smoke machine which I didn’t find before. The smoke was coming out on the bottom side of the throttle body linkage near the spring, so can I assume this is a significant vacuum leak? If so, is this a common leak in this location?

 

[diesel farmer]

I just read some posts which seam to indicate that a vacuum leak on the spring located under the throttle linkage isn’t significant.

 

[Mustang5L5]

Likely not big enough to cause the issues you are seeing.

That tps wiring though….that’s really suspect

 

[diesel farmer]

Update — installed a new TPS and replaced the connector to it. Car idles much better. Decided to pull intake and am working on the explorer intake swap. I appreciate the comments from the folks on this thread.

 

[General karthief]

Well good!!
now keep us updated on the intake swap
Maybe even some pics, I get tired of reading.

 

[diesel farmer]

General -- I attached a couple of pics and a more thorough update for your entertainment!

Intake -- I'll keep you posted on the swap. I think I have the parts, but need to clean everything up and get to work.

T5 -- I pulled the T5 transmission. It wasn't shifting the best and the oil pan needed to be removed and I really didn't want to pull the engine so I removed the tranny and then lifted the engine up high enough to remove the pan with the engine in the car.

Oil Pan -- See pic of the bent oil pan that was seriously leaking. Going to install a new oil pan -- some knuckle head must have tried to jack up the engine under the oil pan! It also has the wrong block plate as seen in the pic. Fortunately, the oil pan doesn't have any metal shavings and the bottom end doesn't look to bad, but the oil was very thick black and likely not changed recently. I don't know how many miles the engine has on it and I don't see any sign of it being rebuilt. I might pull a couple of the caps and see what the bearings look like. I'm leaning toward installing a new timing chain, oil pump/rod/pickup along with seals and then putting on a new pan and hoping the bottom end holds up for a while - is this a good plan or should I pull the motor and install a crate motor?? I'd like a reliable ride, but don't want to get a crate motor right now.

Steering Rack -- I also went ahead and remove the rack since it's leaking profusely -- but note that I didn't have to remove the rack and was able to get the oil pan off with the rack on the car. Still considering the best option to get an upgraded rack -- maybe an upgraded SN95 that is rebuilt by a reputable small town shop?

I'm not sure what the forum rules are, but maybe I will need to start a new thread if I keep up a discussion on this somewhat convoluted progress?

 

[General karthief]

We can fix this easier than swap'n a spark plug on a one lunger.
There, fixed

 

[diesel farmer]

I had to pry out the injectors from the explorer lower intake. After an initial cleaning, here is what it looks like.

How clean do the injector ports need to be for the injectors to seal properly and not leak?

Any ideas on a good technique to polish the ports without going to a machine shop? Maybe use some sandpaper on a Dremel?

 

[General karthief]

Clean them with some brake clean and a rag, no dirt/debris. I think polishing the intake runners will not get you anything, make sure the gasket does not intrude into the port area.
JMO