91 ST185 injector issue

Fhawman

New member
Afternoon!

Moving my post thread to the help section from the new member forum.

91 white ST185, in-laws purchased new, was well maintained until about 5 yrs ago when my father in law developed dementia and parked it in the field across from his house and never touched it again. I brought it back to Las Vegas to get it going again. It has NO dents, NO rust, paint great except oxidation which I already removed.

SO far I have:

Removed/cleaned tank (was bad, sat empty the whole time)
Replaced fuel pump
Cleaned fuel lines between tank and filter
Replaced fuel filter

It starts and runs now, but cylinder #1 wont fire (engine seems to be smooth otherwise). Verified spark at the plug so I'm guessing its an injector issue. Anyone have any suggestions short of pulling the injector before I do that? I'm guessing getting the injector out is a PIA but I've never worked on one of these.

Thanks in advance!
 
Interesting opportunity here for you with this find.

How have you confirmed that it is #1 cylinder misfiring? How have you confirmed that #1 cylinder's spark plug is firing properly?

I can't get to the ST185 in my garage at the moment, but I'm assuming #1 cylinder's spark plug is accessible without taking off the intercooler. Removing the intercooler is not very difficult though to check the others.

If you can access #1 cylinder's spark plug easy enough to remove it, I would suggest you check #1 cylinder's compression pressure while the spark plug is out to see what that is before tearing everything apart to access the injector. Do the easy things first.
 

FC Zach

Active member
Fhawman":2vd9cn6q said:
Verified spark at the plug so I'm guessing its an injector issue. Anyone have any suggestions short of pulling the injector before I do that? I'm guessing getting the injector out is a PIA but I've never worked on one of these.

Besides cleaning/replacing injectors, check the compression and on all cylinders. I'd check the compression before anything else (if you haven't already).
 

Fhawman

New member
Thanks for the replies.

I’m sure it’s #1, nearest the front of the engine, because the idle doesn’t change when I pull that wire from the distributor, the others make the engine die.

I had the plug out on the wire with a spare in the cylinder and it sparks fine. The plug doesn’t show any wet fuel either so another sign that the injector isn’t right.

I can check the compression easy enough, will try to get that tonight.
 
Another possibility on these engines is the plug wire arcing to the metal tube in the cylinder head. Can't tell you how many times this has happened to me, especially with non-OEM spark plug wires. This is easy enough to see if it is happening if you pull the wire off the spark plug and slowly raise it a little above the top of the spark plug (still in the tube), especially if you can do this in the garage or in a dark place.

I would rule out all other possibilities before tearing it down to get to the injector. Injectors on these engines have been very reliable.
 

Fhawman

New member
93celicaconv":8vtibzow said:
Another possibility on these engines is the plug wire arcing to the metal tube in the cylinder head. Can't tell you how many times this has happened to me, especially with non-OEM spark plug wires. This is easy enough to see if it is happening if you pull the wire off the spark plug and slowly raise it a little above the top of the spark plug (still in the tube), especially if you can do this in the garage or in a dark place.

I would rule out all other possibilities before tearing it down to get to the injector. Injectors on these engines have been very reliable.

Thanks, good suggestion. I can do that tonight also.
 

Fhawman

New member
Ok it looks like I might have some time this weekend to make some progress on this.

I tested the compression and it was 175 psi, which seems good to me. I'll look at the wire sparking in the tube mentioned above tonight but if the wire is good I guess next step is to pull/test the injector.
Should I just pull all of them and have them cleaned by a shop?

Also, mother-in-law said it didn't feel like the turbo was boosting when it was parked. I'm guessing vacuum leaks and waste gate actuator are the things I should look at for that.

I could drive it around the block but I'm not sure if with only 3 cylinders working it would tell me much about the turbo.

Any suggestions are welcome, I'm a fair mechanic but have very little turbo knowledge.

Thanks!
 
Fhawman":w1s5tro4 said:
I tested the compression and it was 175 psi, which seems good to me. I'll look at the wire sparking in the tube mentioned above tonight but if the wire is good I guess next step is to pull/test the injector. Should I just pull all of them and have them cleaned by a shop?

Also, mother-in-law said it didn't feel like the turbo was boosting when it was parked. I'm guessing vacuum leaks and waste gate actuator are the things I should look at for that.
175 psi on that cylinder is good. Suggests the valves and rings are good, and timing must be pretty good.

First verify your spark plug doesn't have an break in the for that part that is within the spark plug tube. Many times, you can't even see a break in the insulation, but the significantly high voltage can. If that cable passes the spark leak test through the insulation, and you know your spark plug is good, yeah, best to take a good look at the injectors.

If the #1 cylinder injector turns out to have a faulty coil, I don't think any shop services injector coils. They can clean them, but that doesn't help a faulted coil. Best to get a replacement injector, then take all of them to a shop to have them cleaned and calibrated.
 

underscore

Well-known member
If it sat for 5 years I'd probably get the injectors cleaned and flow tested either way. Then you know what kind of shape they're in and don't have one cylinder running lean at full boost or something.
 
Fhawman":17awdgs0 said:
Also, mother-in-law said it didn't feel like the turbo was boosting when it was parked. I'm guessing vacuum leaks and waste gate actuator are the things I should look at for that.
Sounds like a good plan on the injectors.

Also, the turbo should not be providing any kind of boost when the car is idling parked. It better not. How would you control an 800 RPM idle speed if one expects turbo boosting with no engine load?
 

Fhawman

New member
93celicaconv":2ig8rgee said:
Fhawman":2ig8rgee said:
Also, mother-in-law said it didn't feel like the turbo was boosting when it was parked. I'm guessing vacuum leaks and waste gate actuator are the things I should look at for that.
Sounds like a good plan on the injectors.

Also, the turbo should not be providing any kind of boost when the car is idling parked. It better not. How would you control an 800 RPM idle speed if one expects turbo boosting with no engine load?

I knew it doesn't boost at Idle, that's why i mentioned taking it around the block. "no boost when it was parked" meant she didn't think the turbo was working as of the time they quit using it.

Now to find a good shop for the injectors here in Vegas!
 

Fhawman

New member
93celicaconv":2ou965ju said:
Written sentences can be interpreted differently than intended - thank you for clarifying the intended meaning.

lol, I realized how it sounded as soon as I saw your post, funny how if it's in your mind it should be obvious to everyone else :)
 

Fhawman

New member
Well, one new injector and a clean on the other three, plugs, cap, rotor, plug wires and its running nice and smooth. Had 170psi ish on all cylinders so I guess it'l be good for a bit.

Turbo seems ok, at least the in dash meter shows boost and it feels pretty good, I expected to feel the boost more but I don't have any experience with this car so who knows. Turbo spun by hand very smooth and had no play.

Now on to all the other things it needs...

Thanks all for the info!
 

silverarrow

New member
My personal opinion only, out of all the turbocharged cars I've ever driven and sat in, and the three st185s I've owne, All Tracs feels like a normally aspirated engine even when boost kicks in.
 

underscore

Well-known member
With the intake piping being as short as possible the turbo comes in very smoothly at very low revs. The SW20 MR2 with the same engine has a bit of lag and then a kick as it comes in whereas my car is seamless.
 
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