Let's see how good you are!

[SHO_Gary]

Since 1992 I have been the proud owner of 11 different Gen.1&2 SHO's. I have seen alot of different problems present themselves over the years. I do my own mechanic work on them and I have several Ford mechanic friends that are SHO lovers as well. The following problem with this car has alot of us wondering.....so here goes.

I will keep this short because if I typed everything that has been checked and the reason behind it I could go on for pages. I will give as much info in the shortest way possible.

The car.....1993 SHO with a 5-speed. 200,972 miles.
New rod bearings and rings at 160,000 miles.
Upper end done at 170,000. i.e. valves adjusted, gaskets, plugs, etc.
New fuel pump at 170,000 as well. This is what the other owner had documentation of. I bought the car 600 miles ago as a 'parts' car. Since I could not stand to see a SHO just die I decided to see what was wrong.

When I first took ownership it would start and bearly run. Meaning, if you let it idle or drop below 3500 rpm it would 'flood' and die. I picked it up in Wyoming and somehow made it back to Utah. After much looking I found that the MAF had been changed to one from a Mustang and that the BARO sensor was bad. I put a new BARO sensor in and put the correct MAF in it from another 1993. At this point I also did the crank and cam sensor, seals, water pump, etc.

Now let me describe how it runs and what I have done over the past month to fix it. Now you can start it right up when it is cold. It will jump up to 3000 rpm and sit there for 45 seconds and then take 2 more minutes to come back down to 1100 rpm. It will idle at 1100 for a long time(like 5 minutes or longer.) Yes I have done a idle reset procedure with the computer being cleared. If you have it at an idle(1100 rpm) and you just crack the throttle, it will stumble and die. Sometimes you can crack the throttle and it will rev up but once it does rev up, it will go to an 3000 rpm idle and does not want to come back down to 1100. I am sure you are thinking at this point IAC, just like I was. I got a new one and put it on. Did not fix the problem.

If you take it for a ride here is what you get. Of course the idle is too high so it 'races' along. When you stop the idle is all over the place. It is almost impossible to drive it at any speed and anything under 3000 rpm. If you get above 3000 rpm and 'stand' on it you get a 1-2 second stumble and then it takes off and from 4000 to 7000 rpm it goes like a *****-ape. And then when you have driven for 5 minutes or so the problem of going below 3000 rpm comes back. It dies most of the time if you drop below 3000. Once it dies it smells flooded and pulling the plugs confirms it. Once you **** it when it does this. Restarting it by cranking is almost impossible. Most of the time you have to roll start it along ways to get it to restart. Plugs are black but not fouled and they are new motorcraft ones. Also taking a drive with the MAF unplugged will get the same result. Once restarted it will blow alot of black smoke out and spew stuff out the tailpipes all over the driveway. It is just running way to rich. Plus it uses alot of fuel right now.

Ran the codes and I got a 21, coolant temp sensor out of range. I put a new one in. I am talking about the one in the heater line not the guage. Still same problem. I have several SHO's so I took my 1992 with 110,000 miles that runs perfect and started swapping parts.

Changed the MAF and the IAC(again) from the 92. Same problem.
Then put the BARO sensor and the DIS from the 92 on. Same problem
Put the cam sensor on from the 92 for the fun of it. Same problem.
Checked the ground on the back of the motor and the wiring going to the fuse junction box. Same problem.
Disconnected the vacuum lines and capped off vacuum ports. Same problem.
Sprayed starting fluid and carb cleaner over entire motor. No leaks, same problem.
Put the throttle position sensor from 92 and an extra one I had. Same problem.
Checked all wiring harnesses on motor. Including the one on the back of the motor. Same problem.
Changed the CCRM with a known good one. Same problem.
Put in a different computer (behind glove box) Same problem.
Then I thought injector problem since it is flooding so bad. Got 6 different injectors and put them in. Same problem.
Then someone suggested fuel regulator issue. Got a known good one and put it in. Same problem.
Put in new fuel filter. The old one was not plugged. Same problem.
Ran fuel system pressure test. It passed. Same problem.
Took off timing cover to make sure it is still timed properly. It was. Same problem.
The car was test driven each time after I did these items. They were not done all at once and then taken for a ride. Once the parts were put back on the 92 of course it went back to running perfect just like it had before. Also I took a MAF from another 93 I have that is running great. Made sure it was clean and put in on. Same problem.

So there you have it. Why is it running so rich and flooding so bad? Also I did change the temp sensor in the airbox and got the same result. And I did disconnect the o2 sensors and reset the computer just for fun. It ran just a bad as always so I plugged them back in.

Have fun with this..........and I look forward to all your responses! Like I said I wanted to keep it short. Give me a call if you want a more detailed report on a certain item. 435-668-0684. I will check this website each day to see the comments. Thanks to those who keep this website up. It does help us crazy SHO people alot!

 

[SHOspazz92]

Vacuum leak.

 

[LJRuddy]

Random thoughts as I read the post:

Have you taken the fuel rails and injectors off the motor and cranked it over to make sure all injectors are flowing properly and not sticking?

Have you put a volt meter to the throttle position sensor and made sure voltage increases smoothly throughout the entire range (idle to WOT)?

Just for fun, take a heavy gauge wire and fasten it from the computer ground (small black wire attached to the negative battery terminal) to the fender. Do this with a wire attached to one of the 4 mounting screws on the DIS.

What kind of voltage is the idle air bypass getting?

Have you ran across all grounds with a volt meter and made sure everything is grounding out?

Wiggle test?

From the sounds of things, you have a vac. leak but I am assuming you capped off everything properly and sprayed everything with the starting fluid. Because of that assumption, I am going to say something electrical isnt working correctly.

 

[lowc]

reread that seen you already swaped computer and ccrm.

 

[jimtash]

Throttle body idle screw has been messed with. If so, there's a procedure to reset the idle from it, disconnect the battery and allow the computer to relearn its idle from that base setting after hooking everything back up. Nothing will matter as long as that screw is out of adjustment.

 

[LJRuddy]

Throttle body idle screw has been messed with. If so, there's a procedure to reset the idle from it, disconnect the battery and allow the computer to relearn its idle from that base setting after hooking everything back up. Nothing will matter as long as that screw is out of adjustment.

Wrong. Having the screw in the incorrect spot will affect idle, engine deceleration, shift points if an auto, and a couple other things... But it wont affect anything while the car has any throttle input. Having the idle screw set too far in will make the engine act like your foot is slightly pressing on the gas pedal all the time. Nothing more.

 

[stevoboyd]

i would try new o2 sensors, being o2s and maf and coolant temp sensor(until its at operating temperture) would be the things that would make it run that rich, (that i can think of). if none of those solve your problem i would use a lab scope and get a pattern for your injectors to see if there staying open to long

 

[SuperHO]

dammit, i had this same problem on my old 92 once...and damned if i can remember how it was solved! for some reason, my mind wants to tell you to check for leaking at the fuel rail, but i have doubts...can't hurt to check anyway. also...crazy thought...are the crossover tube hold-down bolts good n' tight? how about the intake hose? any holes? try replacing the canister purge selenoid...those can cause goofy ass issues as well, and won't always throw a code.

 

[SHOtime2511]

Vacuum leak.

This^

 

[SVOFANATIC]

I'm going to throw a h3ll of an idea out there but I would almost say you have a wiring problem. I felt with something similar for 6 months last year and found a wiring issue. This is up to you but I would swap wiring harnesses between the 93 & 92 and see if the problem follows the harness. It sounds like a maf issue. When me last car did this it was
the maf causing it but I tested it and everything was good turned out to be messed up wiring. At the 4000rpm range the car went like crazy as you describe and had horrible gas mileage as well. At the 4k rpm rage the car went into closed circuit mode so the ecu went off of preset peramiters and drove like normal. It's alot of work but see as it looks like you've check most everything this seems like your most likely. Also since you got the car from someone else you don't know if this situation just happend or did someone mess with something to cause this? The only thing that bothers me with this is the no codes aspect. Have you seen if the ECT code was still there after the change and clearing the codes?

 

[rubydist]

I agree w/ the wiring issue diagnosis - I suspect the wiring for the tps / intake air temp / mafs circuit. look those over carefully to see that all connectors are clean and tight.

The other thing I suspect is that one or more injectors do not shut off properly. Do you have a set of injectors to swap in?

You may well have more than one issue that makes this whole thing muddy.

 

[93rev2sev]

Vacuum leak after MAF.

 

[zak]

Unplug EEC, clean both sides with electrical contact cleaner.

 

[SHO_Gary]

Great comments Gentlemen....keep them coming! I love it when the think tank gets flowing!

I am not ruling anything out that has been posted so far...like I said great comments. Just keep these things in mind while you are thinking.

Yes I do have 6 known good injectors and they were swapped in.
Yes the fuel rail was cleaned and inspected for cracks and leaks after the install of the regulator.
Yes vacuum leaks are a pain indeed. That is why I capped all ports at the intake off and then tested, with no luck.
Maybe on the vacuum leak after the MAF. But I have had the throttle body off several times and looked for cracks etc. And put a very heavy coat of starting fluid then carb cleaner over that area as well. No change.
I did look at the throttle body when I had it off. It does close properly and the screw is set in the right postion. All ports are clean as ever as well.
If you have had a problem with vacuum leaks.......please chime in and tell me where your problem was and I will check mine. I will also check the canister purge solenoid as well.
At the moment I will not rule anything out even though I have taken action on a previous day.
The flow test on the injectors is a good idea, I did not do that when I installed them. Mostly because they came from a perfect running engine. But you know how things change!
And the electrical comments will all be tried and tested. With how this acts right now, it has to be something like that!

Thanks again and keep the solutions rolling in. The winner gets.....????

 

[93rev2sev]

Vacuum leaks are not all correctable.

If you have a broken ring land or burnt valve other internal leaks, the engine won't pull a consistent vacuum.

It sure sounds like, with all the stuff you've done to fix it, it's time for some real diagnostics.

You need to perform a complete vacuum and compression test.

 

[ViPER1313]

This really sounds like a major vacuum leak. Did you make sure all the hose clamps on the intake manifold are tight? When say you capped the vacuum hoses, did you disconnect and cap the huge vacuum line on the back side of the intake manifold (that feeds the brake booster?) Are you sure the manifold is seated properly on the heads?

EDIT: What happens if you unplug the IAC while the motor is running? Will it still idle?

 

[SHO_Gary]

Yes on the capping the big vacuum line on the intake as well as the little one next to it. I put my finger over the small one and the big one and it does pull a strong and very steady vacuum. I will perform the compression and vacuum tests that 93 rev to sev suggested. And I did triple check the seating on the manifold. If you unplug the IAC it does **** the motor. And if you leave it unplugged and try to start it, it wont start.

Just a further thought on the vacuum leak. If it had one, why after it started and came down off its high rpm idle(3000 rpm) to 1100, why would it sit there and idle for 5 minutes at 1100 rpm steady? And then at that same 1100 rpm idle, when you just crack and I mean crack the throttle would it stumble and die? And if it doesnt die it will resume its 3000 rpm idle. Chime in......I am new to vacuum leaks I will admit!

 

[rubydist]

your car is possessed - you need to send it to me for exorcism. btw, my fee for the exorcism is that I keep the car.....

guys, vacuum leaks very rarely result in the engine running rich.

Gary, if you unplug the iac and the warm engine dies and/or will not idle, that means the throttle plate is not adjusted properly. a properly adjusted throttle plate will allow the engine to idle at around 500 rpm w/ the iac unplugged. I would tweak the throttle plate stop screw until it idles w/ the iac unplugged, then I would do the idle reset and try all this over.

btw, I just got a new iac for my 92 and the new one was stickier than the 15 year old one it replaced, so I am currently awaiting a replacement from rockauto. the point is just because the iac is new does not mean it works right.

 

[LJRuddy]

guys, vacuum leaks very rarely result in the engine running rich.

An improperly set idle stop screw will not result in the car running rich either. A vacuum leak will allow unmetered air into the engine which will most definitely mess with air/fuel ratios especially since the car isnt factoring for extra air flow past the MAF.

Go unplug your brake booster line and tell me what your mpgs look like. Do the same after messing with the idle screw. :wave:

 

[firebat45]

You said you replaced the coolant sensor in the line, not the gauge one. There's actually 3 coolant sensors (go Ford!), the one in the line is for the EATC. Both of the other sensors are in the thermostat housing, the single pin sensor is for your gauge and the 2 pin sensor is for the ECU. The ECU sensor is easy to miss if you don't realize it's there, it's way down at the bottom rear, covered by other hoses and wires.