Mechanic's opinion needed...

[Lmo1131]

I don’t have the distributor readouts that indicated a reason to replace. My bad…

I ginned up a code reader yesterday; All systems okay; EGR not responding; and low idle.

Then the weirdest thing happened. After l took the code readings l went for a drive and virtually everything was normal, no idle stumbles, no lost throttle response, highway speeds were great, idle at the end of off-ramps was excellent (no stumbles).

Today… back to all the previous issues.

At this point l have no faith in the shop l’ve been using.

I can swap out the TPS (don’t know if it needs calibration). EGR is probably within my skill range.

Motorcraft still makes a TPS for it. “Standard” is an old American brand. NTK makes one.

 

[Ark]

Weird one. One thing you can do is put a multimeter on your new throttle sensor, measure resistance across the movement range, and compare it to the one on the car to see if you can spot it dropping out. Normally mix is set by mass airflow and manifold pressure sensor data along with O2, not throttle position, but '89 is old so I'm not sure how it works. Rockauto shows a MAF sensor, those can be tempermental but can be cleaned with a specific cleaner from the parts store. Might identify the culprit if cleaning it reduces the occurrence.

Intermittent driveability is hard to diagnose. Gummed up EGR can do it when that valve sticks open, lets exhaust in at low RPM, and jacks up the mixture. Gets better at highway speed because the much greater incoming air dilutes it down to normal exhaust gas recirculation. They have a moving solenoid valve that could stick intermittently.

If you can view live data with a scan tool, you can watch sensor values and look for obviously goofy stuff happening. That's a way to test throttle position, too.

 

[Lmo1131]

If you can view live data with a scan tool, you can watch sensor values and look for obviously goofy stuff happening. That's a way to test throttle position, too.

Just got back from my local parts house (O'Reilly Auto Parts); they offer free scans; unfortunately they only have OBD-2 scanner.

Built in 8/1987 the Escort has the first generation of OBD system (OBD-1), which was mandated for 1988 model year vehicles. As I understand it, OBD-1 system codes are specific to a given vehicle/manufacturer. OBD-2 didn't kick in until '96.

My local Forde dealer will not touch anything older than 2000, and the FoMoCo Parts Department cannot even find parts for it (given the VIN, and Calibration code).

So I guess I'm facing a replace-it-until-it-works situation.

 

[injb]

Just got back from my local parts house (O'Reilly Auto Parts); they offer free scans; unfortunately they only have OBD-2 scanner.

Built in 8/1987 the Escort has the first generation of OBD system (OBD-1), which was mandated for 1988 model year vehicles. As I understand it, OBD-1 system codes are specific to a given vehicle/manufacturer. OBD-2 didn't kick in until '96.

My local Forde dealer will not touch anything older than 2000, and the FoMoCo Parts Department cannot even find parts for it (given the VIN, and Calibration code).

So I guess I'm facing a replace-it-until-it-works situation.

I'm no expert here, and certainly not a mechanic, but as an owner of a 1989 car with early electronic fuel injection, I want to caution you against the replace-it-until-it-works approach. That can get expensive. Many things can be tested with fairly low-tech methods.

* TPS sensors can generally be tested with a multimeter. If it is the type that just has microscwitches for closed/open, it's trivial. If it has a potentiometer, then it's best to hook up a voltage and test the wiper with the voltmeter (this will be more sensitive than using the ohmmeter).

* O2 sensors can be tested with a voltmeter

* vacuum leaks can be tested with carb cleaner, or with a home made smoke source (I've seen videos of people using cigars for this)

That said, some things should be replaced due to age without testing, like fuel filters for example.

The downside to testing stuff is that it's time-consuming but still probably faster than waiting for parts to arrive in the mail.

 

[bobzilla]

That era of fords were notorious for the ignition control modules on the distributor dying, or the pickup coil internally going bad. We had a few. And no, you're not going to find any dealer with a tech old enough to know that chassis lol.

 

[d.kaufman]

Just got back from my local parts house (O'Reilly Auto Parts); they offer free scans; unfortunately they only have OBD-2 scanner.

Built in 8/1987 the Escort has the first generation of OBD system (OBD-1), which was mandated for 1988 model year vehicles. As I understand it, OBD-1 system codes are specific to a given vehicle/manufacturer. OBD-2 didn't kick in until '96.

My local Forde dealer will not touch anything older than 2000, and the FoMoCo Parts Department cannot even find parts for it (given the VIN, and Calibration code).

So I guess I'm facing a replace-it-until-it-works situation.

If your anywhere near NWI I can scan it for you. I have OBD 1 capabilites at my shop

 

[rhamersley]

Just got back from my local parts house (O'Reilly Auto Parts); they offer free scans; unfortunately they only have OBD-2 scanner.

Built in 8/1987 the Escort has the first generation of OBD system (OBD-1), which was mandated for 1988 model year vehicles. As I understand it, OBD-1 system codes are specific to a given vehicle/manufacturer. OBD-2 didn't kick in until '96.

My local Forde dealer will not touch anything older than 2000, and the FoMoCo Parts Department cannot even find parts for it (given the VIN, and Calibration code).

So I guess I'm facing a replace-it-until-it-works situation.

If I recall correctly, the OBD-I was the one you could jump two terminals in the connector and the check engine light would flash a numeric signal. Been ages since I did it, and I could be remembering wrong, but might look that up on the net.

 

[bobzilla]

If I recall correctly, the OBD-I was the one you could jump two terminals in the connector and the check engine light would flash a numeric signal. Been ages since I did it, and I could be remembering wrong, but might look that up on the net.

GM was for sure. Ford depended on the chassis/setup. IT's also been a long time.

 

[DoggyDaddy]

If your anywhere near NWI I can scan it for you. I have OBD 1 capabilites at my shop

He's in California so... Still a nice gesture!

 

[rhamersley]

GM was for sure. Ford depended on the chassis/setup. IT's also been a long time.

Makes sense. My first car was a manual 83 Buick Skylark that I used that trick on a few times in college.

 

[Lpherr]

The part number and price:



Image:



I recommend only Motorcraft for most Ford parts.
I tried 3 different brands for an IAC (because Motorcraft was $300 compared to just over $100) and none would work.
I replaced with the Motorcraft, and was perfect from the first start.
YMMV

 

[bobzilla]

Makes sense. My first car was a manual 83 Buick Skylark that I used that trick on a few times in college.

I actually did it fora co-worker last week. He bought a MINT 94 C2500

 

[Lpherr]

He's in California so... Still a nice gesture!

A short Sunday drive.

 

[thunderchicken]

Just got back from my local parts house (O'Reilly Auto Parts); they offer free scans; unfortunately they only have OBD-2 scanner.

Built in 8/1987 the Escort has the first generation of OBD system (OBD-1), which was mandated for 1988 model year vehicles. As I understand it, OBD-1 system codes are specific to a given vehicle/manufacturer. OBD-2 didn't kick in until '96.

My local Forde dealer will not touch anything older than 2000, and the FoMoCo Parts Department cannot even find parts for it (given the VIN, and Calibration code).

So I guess I'm facing a replace-it-until-it-works situation.

Yeah Ford's OBD-1 system was the Ford Star tester. Lol I used to have one but got rid of it several years ago.

Clean the throttle body, replace the TPS and while idling take a small hammer and tap on the EGR valve. It it's sticking sometimes that will jostle it free. The EGR valve shouldn't be open except while driving, primarily at highway speeds. So, it's possible that's the problem as it seems to run fine at highway speeds but only acts up while in stop & go conditions.

That's where I would start

 

[thunderchicken]

If I recall correctly, the OBD-I was the one you could jump two terminals in the connector and the check engine light would flash a numeric signal. Been ages since I did it, and I could be remembering wrong, but might look that up on the net.

It's been a very long time, but I think that was pretty much just a GM thing.

 

[Lpherr]

It's been a very long time, but I think that was pretty much just a GM thing.

The test light is to monitor the flashes.

 

[thunderchicken]

Someone mentioned using a DVOM (volt meter) to sweep the TPS. Yes, that is a test method. However, you have to sweep it super slow or you can miss the bad spot in the sensor.

 

[thunderchicken]

View attachment 306048

The test light is to monitor the flashes.

I didn't recall that. But, the diagram looks somewhat familiar now. But as I stated above, I actually had one of those black box Ford Star testers years ago so never had to try jumping the connectors. Man looking back, those testers seem so prehistoric compared to what we have now. I remember having to step on the brake and turn the steering wheel a half turn for it to complete a self test and pull codes on some vehicles

Dang, now I feel old. I can't help but wonder if this is what my old friend Churchmouse felt like at times when he dug back in the memory bank.

 

[Lpherr]

I didn't recall that. But, the diagram looks somewhat familiar now. But as I stated above, I actually had one of those black box Ford Star testers years ago so never had to try jumping the connectors. Man looking back, those testers seem so prehistoric compared to what we have now. I remember having to step on the brake and turn the steering wheel a half turn for it to complete a self test and pull codes on some vehicles

Dang, now I feel old. I can't help but wonder if this is what my old friend Churchmouse felt like at times when he dug back in the memory bank.

Chrysler used the ignition to retrieve the codes. On/off in rapid succession 5 times and stop with key in on position. Codes would flash.

 

[bobzilla]

Chrysler used the ignition to retrieve the codes. On/off in rapid succession 5 times and stop with key in on position. Codes would flash.

and some of the buicks and caddies with the digital climate control used those. Such a weird era. Just kinda do whatever.