• Hint: Use a descriptive title for your new message
    If you're looking for help and want to draw people in who can assist you, use a descriptive subject title when posting your message. In other words, "1998 Town Car" isn't going to indicate to anybody that you need help. However, "Need help with my 1998 Town Car" will. Be as descriptive as you can. Please use common sense... This message can be closed by clicking the X in the top right corner.

Misfiring 88 LTC

mannebk

Member
38
13
8
Germany
Folks,

I bought a 88 LTC recently. It run fine. I had all fluids, ignition ports like plugs, cables cap and rotor, filters and belts replaced.

After about 300 miles, after I also had the fuel pump replaced, I have a car that has missfireing.

So I pulled the inetia switch connector and
 

Brian J. Patterson

Active member
137
68
28
Northern Illinois
Folks,

I bought a 88 LTC recently. It run fine. I had all fluids, ignition ports like plugs, cables cap and rotor, filters and belts replaced.

After about 300 miles, after I also had the fuel pump replaced, I have a car that has missfireing.

So I pulled the inetia switch connector and
Hi, mannebk.

"So I pulled the inetia switch connector and" and the forum gremlins or whatever ended your post right there. As of when I posted this reply, you are the only one who knows what happened after you disconnected the inertia switch connector.

You can either edit your original post or post a second time with the whole story. Either way, your fellow readers on this forum will then be able to offer advice and encouragement. Congrats again on the new family member.

Good luck.
 

mannebk

Member
38
13
8
Germany
More like the battery gremmlins of my cell phone, but yes, I was occupied with my baby girl so it took me some time to come back here for a finish.



So basically what happened was this:

I drove off, proud as Oscar, with my freshly bought and maintained LTC.

100 mile into my trip out of nowhere the fuel pump died. No funny sounds or anything.

I got towed, 2 days later the shop changed my fuel pump, not the assembly, and I drove off again.

Refueled 2 miles later. By then I had about 50 percent fresh fuel in the car.

200 miles later I go for the next gas stop. Since I don't know how large the tank and the consumption is an my fuel level sender is inoperable. Going to idle I discover a sputtering engine.

So I refuel and take a short look under the hood. Check all cables. no result, no obvious reason.

Then I drive to the side, car sputtering like about 2 cylinders missing.

I park and pull the inertia switch. Car dies. Obviously.

Then I make WOT and activate the starter, to check if all 8 cylinders are similar in compression. They are absolutely identical, no mater the throttle position.

So I conclude I can't fix this, and it ain't dangerous, and got the other 200 miles till home on the odometer. Sputtering and all.

At the border checkpoint I discover, the car seams to run fine in idle.

As soon as I open the throttle, the sputtering is back.

Also the consumption between bord computer and fuel meter at pump won't fit any more.

So at home the car sits a few hours and I then drive to the hospital, sputtering as soon as I'm out of idle.

The car sits 4 days I front of the hospital as they got into preventive Corona lock down and I could choose between staying and don't come again. As fresh father I chose to stay. It's below freezing here. When I drove off today, it works fine. 0.5 hours later out of the shopping mall the sputtering is back but again only with open throttle, not in idle.

I would suspect water, frozen and swimming on top in the fuel line, but since I have had the tank down and emptied and refilled with ethanol containing fresh fuel, that is impossible.

So is suspect the fuel injection valves. I think my shop managed to get some dirt into the line while changing the filter or the new pump nocked some old dirt off the hoses and pipes and clogged the valves. I think the damaged on is dripping, roughly fitting for idle but not more. Or they got heat sensitive...

Any other ideas?

Regards Manne
 
Last edited:

JackCisco

Member
55
21
8
TPS is bad? If you have a volt meter on continuity you can test it by probing the connector and actuating the throttle.

Congratulations on the new family member!
______________________________
 

mannebk

Member
38
13
8
Germany
Thanks.

TPS = Throttle Position sensor? Is it just a switch for idle and WOT or is it a poti to give reading for positioning?

why would that one make the car missfire? (i know of rough idle, dieing, etc. pp., but no missfire in driving mode)

Yesterday I had it again. Car parked for 24h. Drove off to the shopping center. 5mi, 8km, no missfire, parked, go shopping. when I took the pictures half an hour later, it was still ideling smoth and driving was okay. no missfires.

then an other 5km later at an other mall I returend after shopping for 2 hours, startet up fine, idles okay but drove like a bucket with the usual missfire.

vid of engine idle: New video by Manne BK

Manne
 

JackCisco

Member
55
21
8
Yeah it gives a reading on the position of the throttle, might be worth checking unless you know for certain that it is misfiring? It was just interesting because you said it was when you accelerated.

I can't remember if this year has any cam/crank position sensors.

Have you removed the distributor cap to check the contacts for excessive wear? (might not be the issue as you said it is when you accelerate).

I also know from experience that the ignition control module on the side of the distributor can go bad, but that's usually a straight engine cut out and either when it gets hot, then comes back to life when cold or dies completely.
 

mannebk

Member
38
13
8
Germany
I dumped a injection cleaning fluid in the tank.

I don't believe in that stuff..

But it seems it did work, no missfireing since shortly after. But I only have done 60km since then. And only around the block. so the car never has been hot. Maybe the injectors get stuck wenn they get hot on long high-speed Autobahn runs.

However I already ordered an innova 3145 that's an obd1 test unit.

Well soon know more.

Cheers
 

mannebk

Member
38
13
8
Germany
Today I got my code reader. It says 34 in the engine off test.

That's what the book says about 34.

What the heck, I know egr only for diesel engines. In gasoline the throttle is closed, no need for exhaust gases to return to wast energy for getting them compressed and released again with no work need done by that gas.... It seems I have some study to do.

Somebody here may want to explain to me where I find this valve?

Cheers manne IMG_20200322_213929555.jpg
______________________________
 

mannebk

Member
38
13
8
Germany
For running test I get for cylinder the code 8

And for fault codes
94 air diverter solenoid circuit fault
44 thermactor air system fault
34 defective egr pressure transducer sensor
74 brake on/off boo switch fault, not activated (I guess that's my fault for doing it alone)

Some ideas?
 

mannebk

Member
38
13
8
Germany
And for cylinder balancing the computer reports 90 no problem, so I guess the cleaner really did work, well that was a first in 25 years and about 20 classic cars I've owned or still own.
 

mannebk

Member
38
13
8
Germany
Oh by the way, I have a consumption of 10.1 mpg and 23.2 l/100km

But I was doing fast cruises. +80 mph /130kmh for hours.

And now +1 hour ideling and testing.

Still at my 500miles drive from NJ to ON mostly at 70mph I got not that much better consumption it was at about 17l/100km or 14 mpg

And btw before I did start today's testing I did push the LTC way beyond the digital dash maximum speed of 137 kmh or 85 mph. Google told me I was doing 150 for 40km. So I guess that got the drivetrain warmed up some :)
______________________________
 
Last edited:

JackCisco

Member
55
21
8
I'd be scared mine would break somehow if I drove it that fast 😅

Something else to consider in the future is that the diaphragms in the EGR valve can split which prevents vacuum from opening it. Just something to consider if it happens again! Replacements are cheap.
 

JackCisco

Member
55
21
8
Thanks for the advice, if it's anyway shaky, I'll go with a new one.

Yes I know 100mph is fast for most of the world. However I am a German :), let me tell you, it's not "fast" in any way at all
Oh yes definitely with your Autobahn! Although I have no reason to with all the work I've done on it, I would feel like my 1985 TC would break somehow!
 

mannebk

Member
38
13
8
Germany
You made my day :-D

And yes you are probably right. Also I have been on the Autobahn with a 54hp vanagon with a 2 ton Trailer on the hitch doing uphill 25kmh and getting the finger from overtaking truckers. And doing downhill still less than the permited 80kmh and getting even more fingers from truckers. And I made it home with no deformation on the rear end...
 

HTML

Top