93 Typhoon Missing at idle, drives fine.

J

JoeSupra

New member
Just bought this 93 typhoon days knowing it had a rough idle. Idle kinda fluctuates and has a small sound that kinda sounds like a miss. Was wondering if you guys could tell me to comfirm. Here's a video.

https://youtu.be/1vhvLTH4yYg

I just did a FULL tune up today cause I was told that's what it needed. I also changed the 02 sensor for the sake of it. Well it's still there. I poured some seafoam in the brake booster line and see if there was an leaks in the vaccum lines. Couldn't see any smoke in the bay. Could it be a leak so small that it only leaks under pressure? I don't want to believe I have a low compression motor. Thats what I waa told it could be. The truck drives really good, hits 15 psi on the factory gauge quick, doesn't smoke, motor is quiet. All I hear is a little tick from the injectors I'm assuming.

Truck has ATR pit bull exhuast and chip with a walbro fp. I don't if that helps but figured ido mention it.
 
Gnocide

Gnocide

turbo game burt reynolds
Re: 93 Typhoon Missing at idle, drives fine.

dont know enough about the issue but that sounds like 90% of the trucks out there
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

Gnocide said:
dont know enough about the issue but that sounds like 90% of the trucks out there
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So is the sound normal? Truck has no check engine light. I feel it runs like a champ. The temp gauge looks a little low. I think my heater core is leaking but that is another issue. I don't think it has anything to do with this unless it's causing the truck to limp cause it's not hot enough??
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: 93 Typhoon Missing at idle, drives fine.

The idle looks perfectly normal for a SyTy. Stock they are seem to have an occasional miss.
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

DaveP said:
What was the compression when you checked it during the "FULL tune up"?

Not everyone checks compression every time the plugs are out like I do, but a compression check should always be included in a tune-up. Especially on these engines. Especially on a new acquisition with a miss.

One can guess, or one can know for sure. I prefer to know for sure.

In the first part of the vid where the mic is near the exhaust, I hear an occasional "thunk" sound. Is that coming from the exhaust? Is this what you mean by the "miss"? That is not normal. At least not on the 6 SyTy's I;ve owned, or any of the dozens of others I've driven or worked on. Be sure your balancer hasn't slipped, and the timing isn't where you think it is because the marks are wrong. Late (retarded) timing causes incomplete combustion, the residual rich mixture occasionally re-ignites in the exhaust system causing the "pop" or "thunk" that I hear in the vid. Unless you're bumping the camera into something....?
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Compression test was not done due to me not having a tester. But yes that thunk sound you hear is in the exhaust. Other people are saying it'a normal. But I will have timing checked and I will change some other components to see if it helps.
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

DaveP said:
That thunk is NOT "normal". Listen to whoever you want to. Some people know what they're talking about, some don't.


If you didn't check the compression, you didn't do a "full tune up". It's really important. You just don't know if it's OK unless you check it. These engines are very prone to damaging pistons from detonation. Been happening since Kenne Bell took the KR out of his chips and sold the first one back in 91. You bought this thing used, and it has a problem. The way to figure it out is to check things and determin if they are Ok or not. Process of elimination. I've watched guys on here for years screw a set of plugs into the heads and replace the rotor and cap thinking that is the cure-all for what ever ails their SyTy. It pretty much never fixes anything.

Good Luck.
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I'm familiar with cars and mechanics and iv never heard of a compression test being a part of a tune up. But I will take in what you said and use the process of elimination to help solve it.
 
Don W.

Don W.

Stab it and steer it
Re: 93 Typhoon Missing at idle, drives fine.

That is a weird noise. Do you hear it with the hood up? Did that tuneup include wires? My first thought was you've got some cross-fire going on. Might also check that you've got all the plug boots on all the way, cap end also. Might also bang on the cat/muffler(s) and see if anything rattles. Nice steady tach though. Leave out the noise and the idle sounds pretty good to me also.
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

Don W. said:
That is a weird noise. Do you hear it with the hood up? Did that tuneup include wires? My first thought was you've got some cross-fire going on. Might also check that you've got all the plug boots on all the way, cap end also. Might also bang on the cat/muffler(s) and see if anything rattles. Nice steady tach though. Leave out the noise and the idle sounds pretty good to me also.
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No you do not hear it when the hood is up or when you first start the truck. You don't hear anything while driving either. I changed plugs, wires, cap and rotor, 02 sensor. I have an ATR muffler I will check that.
 
Don W.

Don W.

Stab it and steer it
Re: 93 Typhoon Missing at idle, drives fine.

I'm with Dave on the cap, rotor and plugs thing. On the flip side I can usually tell if an engine has a bum cyl, at least one that might need a compression/leakdown, in the way it cranks. Dave's advice is about 99.9% spot on so I ain't gonna quibble.
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

Don W. said:
I'm with Dave on the cap, rotor and plugs thing. On the flip side I can usually tell if an engine has a bum cyl, at least one that might need a compression/leakdown, in the way it cranks. Dave's advice is about 99.9% spot on so I ain't gonna quibble.
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Truck starts right up no problem and truck performance well for what it is. So I'll do a compression test then leak down test depending on the results. I'm hoping this is just a vaccum leak that I can't see.
 
Don W.

Don W.

Stab it and steer it
Re: 93 Typhoon Missing at idle, drives fine.

That noise is almost to sharp/clear to be coming all the way from the engine. Are you saying that it's only there when the motor is warmed up? If you listen you can hear an occasional miss. Different sound than the "tick."
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

Don W. said:
That noise is almost to sharp/clear to be coming all the way from the engine. Are you saying that it's only there when the motor is warmed up?
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Yes it's not there when the truck is first started (closed loop?) When you pop the hood you don't see the motor shake or anything. Motor sounds healthy.That's why I don't know if that's really a miss. Lol I know what a miss is thanks to my supra have past ignition problems.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: 93 Typhoon Missing at idle, drives fine.

I wonder if that metallic noise is something is loose in the muffler or the exhaust banging against metal when the engine does its occaisonal stumble.
 
Don W.

Don W.

Stab it and steer it
Re: 93 Typhoon Missing at idle, drives fine.

Hah! I had couple of bugs actually. Often refereed to a "3 cylinder Vdubs." Used to hear them running around all the time. Cyl 3 was usually the culprit as I recall. No wonder Dave likes compression checks.:rotf:
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

Timing will be checked. Thanks guys for your input. I will report back when I caneed with some updates.

Would a datamaster scan help you guys?
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: 93 Typhoon Missing at idle, drives fine.

Datamaster is always a good idea with these trucks.

I would try checking the timing first like DaveP recommended. After he wrote his response, it reminded me of the noise that my engine made when I guessed at the timing. Just beware that the balancer can spins on these engines so the timing can be wrong.
 
J

JoeSupra

New member
Re: 93 Typhoon Missing at idle, drives fine.

dgoodhue said:
Datamaster is always a good idea with these trucks.

I would try checking the timing first like DaveP recommended. After he wrote his response, it reminded me of the noise that my engine made when I guessed at the timing. Just beware that the balancer can spins on these engines so the timing can be wrong.
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I just tried spinning the balancer by hand with the belt on and nothing. Seems solid. I dont have a timing gun and my odb1 cable wont connect to my laptop yet. Batting 1000.
 
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