is the wiring for an 88 convert independant from factory?

more4u2c · Post by **more4u2c** » Fri May 09, 2014 5:12 pm

hello I’ve been dealing with a hesitation issue with my car since I bought it. been replacing bad parts like mad and it’s not really helping all that much. My question is on a 1988 mustang ASCMclaren did the controls for the top and cover splice into any stock wiring or was it ran completely independent? I ask this because the previous owner had a shop that didn’t know what they were doing try to fix the top controls and made a real mess of everything. So I just ran my own new wiring and bypassed all the hacked up stock stuff seeing how it wasn’t done right and not working at all. I now have the top working fine due to the fact its hooked up straight to the battery bypassing all stock stuff. but I’m now wondering if because of the hack job the previous own had done and me just saying screw it and rewiring everything up independently that somehow that hack job is causing the hesitation issues I current have been having? Any help would be great. I’ve checked all the mustang forums and did everything they have recommended to no avail so I’m thinking it might be ASCMclaren specific issue like the wiring of the top system being hacked apart and put back together all wrong?

Post by **negusm** » Fri May 09, 2014 6:45 pm

When you say a "hesitation issue", you mean a hesitation in the engine revving?

(just being crystal clear here).

I can't think how the top wiring would affect the engine in any way. Even if they somehow spliced into the engine harness, I would think that it would do more than cause a "hesitation".

What have you already replaced?

To me, a hesitation is going to be one of the following:

Fuel starvation. (how old is the fuel pump? test fuel pressure)
Weak spark. (bad coil? TFI module?)
Bad sensor telling the computer to fire incorrectly.

Have you run codes (paper clip method)? I don't think the 88s have a check engine light....so you may not know you have codes in the computer.

I am not fully familiar with EFI stuff but I suppose it is always possible the original owner bypassed a sensor or something.

I would start with the engine harness. ANY cuts/splices/breaks need to be removed/repaired and the harness put back to stock. Look for breaks in the wiring. Bad/loose wiring wreaks havoc. On the older cars, it causes all kinds of goofy issues.

I had an old '96 Probe GT that ran GREAT...until you disconnected any spark plug wire. Then it had a BAD hesitation. Anytime I had the car in the shop...I had to go to Autozone afterwards and get a NEW set of spark plug cables. Then she would run PERFECTLY for years until the next time it went into the shop. I was like magic. I don't know why. I crimped the connections, used the grease, etc....nothing worked until I replaced the wires.

-Mike

more4u2c · Post by **more4u2c** » Fri May 09, 2014 6:54 pm

I hope someone can help me out with my hesitation/idle issue. OK so I bought a completely stock 88 mustang Lx 5.0 AT ASCMclaren edition about a month ago and it had this hessitation/idle issue that I thought would be a easy fix... man was I wrong! The car was like a barn find as It was owned by a old lady whom passed away and I got it for a great deal at a estate sale $500.00!!! Im estimating that the car sat for about 7 years. cobwebs everywhere tires brand new with the lil whiskers still but are 7 years old!!!. the owner kept evey recipt and service record and the newest one was in 2007 so im assuming it was parked and stored after that.

So the issue started out with hessitation when acceleration gradualy from idle to about 2k RPM. after 2k RPM it smooths out and drives normally. at idle it basiclly bounces around at first itll idle fine then the idle dips down to about 500rpm then the car goes all panic mode trying to get the idle back up to normal bounces around then levels out for a second or two then dips down then freaks out etc.

now at first this issue only happened after the car was ran for 30 minutes or longer as long as the trips were under a half hour the car runs great, normal idle no hessitation.

Here is what Ive done to fix the issue that have failed each time...

Replaced intake with GT40 (explorer) intake and fuel injectors
Both coolant sensors
ACT sensor
fuel filter
fuel pressure regulator
fuel pump
plugs, cap, rotor, wires, coil, and distributor
BBK H-Pipe (no cats)
all new vaccum lines
Set timing to 10 degrees it was set at 2!!!
removed all grounds cleaned suface with grinder. (amazing how ford attached them to painted parts)
G3 Alt upgrade w/ upgraded ground wires
New TPS
Base line idle reset performed
Cleaned salt and pepper shakers

Ran all computer test and get 11 codes and a all good 9 for the cyl bal test.

Removed and cleaned the IAC, EGR, MAF.

Post by **negusm** » Fri May 09, 2014 7:04 pm

Welp, I've got nothing, you've replaced a crap ton of stuff. You could completely disconnect the top wiring to see if it makes any difference.

BUT, here is what you should do next:

www.foureyedpride.com

Go to the forums, sign up and post in the tech section. Copy your second post over there.

That is THE BEST place to get a good answer. There are a ton of "older" guys who have DECADES of experience in '80s Fords. Far more mature than most of the other Mustang sites. Tons of them have late 80's/90's setups in their cars.

One guy there (assuming he still is there), JACOOK is like the Ford Whisperer. He seems to zero in on exactly how to figure out what you have to check to know what is going on.

One thing I will say...did you replace the sensors/distributor with FORD parts? Ford makes EXCELLENT engine electronics (but lackluster wiring). Discount auto store parts don't fix tulips and you may have just replaced a defective part with another defective part. This happens a lot.

-Mike

more4u2c · Post by **more4u2c** » Fri May 09, 2014 7:07 pm

thanks mike ill check them out...

Post by **negusm** » Fri May 09, 2014 7:13 pm

Just to say, I edited my reply...you may want to read it again quick.

Make sure you replace electrical stuff with FORD if you can. Lotsa guys get frustrated with cheap Chinese TFI/Sensors/etc. Ford makes excellent electrical parts. Hence why we see 5.0L cars run for 25+ years...with original parts.

-Mike

avmtdan · Post by **avmtdan** » Sat May 10, 2014 2:20 am

One more thing that this generation of cars is notorious for is the Idle Air Bypass valve, they stick, especially if they haven't been run in a while. Pretty cheap fix, but there isnt much to them really. You could try taking it off, cleaning it with throttle body cleaner by douching out the 2 holes that go into the intake and re-installing. Basically the thing controls idle mixture air, but if it is stuck open it could screw up your mixture off idle as well, making the car run like crap.
https://www.youtube.com/watch?v=vFhoNykgQtc

Another fairly common problem is the egr valve sticking, since it handles hot exhaust deposits it will have similar symptoms but is pretty easy to troubleshoot if you have a hand vacuum pump.http://www.squidoo.com/a-simple-egr-val ... e157898775

MRBRUSER · Post by **MRBRUSER** » Sat May 10, 2014 10:53 am

Does the car have mass air? I remember cars sold in California came with mass air. Or does the car have a mass air jumper harness. What your car is doing sounds like a bad mass air unit. Cleaning won't fix it. You would need to replace it.

Post by **negusm** » Wed Jun 11, 2014 2:38 pm

Any updates?

zanrock · Post by **zanrock** » Sun Jun 29, 2014 3:22 pm

To try to help there is some connection to the factory wiring under the left kick panel starting with the 20 amp fuse, but after that its all their doing. There are 3 relays for safe operation/ckecks before operation the tonneau release and jack screw with one of fhose relays working off the e- brake ( without that pulled nothing should work) just so you kinda have a idea of what's going on now at the 20 amp fuse if you pull the fuse and using a meter or a test light have 12 volts on each wire then you know you have a problem and then the fun begins of ffiguring out what's wrong