Ah I didn’t realize that the physical leaking wasn’t the cause, just a visual indicator.
In that case I will attempt to replace them tomorrow morning, I’ll update this thread with how it goes and whether or not it fixes my idle issue.
I would urge extreme caution if you intend on doing this job yourself. This is a multi-layer board which is extremely sensitive to heat exposure. If you do not have the correct equipment or are not experienced with multi layer boards, you risk damage to the board which will require untidy and additional repair work.
I have a strict policy of not repairing any unit that has been worked on by someone else because I got fed up with sorting out other peoples mess. Just as an additional note, I have also seen these boards damaged by so called professionals so chose your repairer wisely. They need to have a temperature controlled vacuum station, hot air station or uv light station to do the job confidently although I know that some experienced people have done this job with cheaper equipment.
Do you have any experience using solder-wick on these boards?
I’ve heard of people having luck using it in this application, now that you mention how tricky it can be I wonder if those people had just been lucky to be successful…
Me personally, I would never use it on one of these boards but different people have different ideas as to what a good repair is.
For me, a good repair is one that is impossible to see. For others, a good repair is one that works when they have finished regardless of what it looks like.
Alright, I found someone who is both qualified and equipped to deal with this sort of thing, and he will be replacing the capacitors either tomorrow or the day after.
I will keep this thread updated with the result of the capacitor replacement.
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UPDATE: I got the four capacitors replaced with a kit I bought off of 3SX.
Got home, plugged in my ECU, reconnected the battery, and the car fired right up as usual.
I let the car warm up, just sitting at idle, and everything was running flawlessly.
Then, after it was up to temp, I noticed that when the fans shut off and when I turned the AC off, the idle got all ugly sounding again. Not surging like it was before, but just like the rpms were really really low or something (tach is broken so idk a number unfortunately).
So the big test, driving it around the block: With the AC off, no fans running, and a messy sounding idle, I put the car into drive and it immediately stalled. Fired it back up and turned my AC on, no more stalling. Turned my AC off at the stop sign, stalled. WTF?
New problem also popped up a few days ago which I thought was completely unrelated. I’ve developed a nice case of belt squeal (sounds like a really frustrated pterodactyl), but only when I first start up the car after it has been sitting for a while. After the car has been running a while, I just hear a really faint intermittent squeaking, more notable while my AC is on rather than off.
Right now I’m thinking there’s a chance I’m dealing with black magic, or some form of small evil elves, or maybe the alternator is acting funny. I monitored the voltage at the battery while the car was running and read a smooth 14.12 volts. Seems low but not low enough to be a problem I don’t think?
P.S.: For those of you still sticking with this thread and trying to help out, you all are amazing people, I admire your patience and willingness to help!
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How old are the belts? Maybe need to be replaced or tightened.
It’s a 1991 so no OBDII to check the rpm. There are some things you can do on the cheap side. Get a rpm measuring gouge… It is usually a laser with sticky reflective tape and stick the tape on the side of one of the cams and measure it that way. Don’t forget 1 engine revolution is 2 cam revolutions, so whatever number you get divide by 2.
Or a free way of just adjusting your rpm with that (screw) that is by the intake hose, so rpm would be higher and should not stall.
Good Luck.
I was wondering about that, are there any codes?
There’s another thread on here where we are talking about OBD 1 code retrieval and you can sweep an analog gauge to display codes. I haven’t done it myself, but my next step would definitely be to get any and all on board diagnostic info from the car I could.
You mentioned your idle sounded low before you even got in it. That makes sense about it dying by going into gear in an automatic, if you watch the rpm on a healthy car you will see it dip. In neutral or park things are spinning nice and easy but in drive while holding the brakes, you force the torque converter to slip which creates drag and a load on the engine. So I wouldn’t be concerned with the engine dying there, it’s the low idle when warm that was the issue I think. Adding AC on is a genius move because when the AC clutch kicks on it, too is an extra load, so the ECU gives a little more fuel to try and compensate without the idle changing too much. So you were getting extra fuel (potentially) and that prevented you from dying with the low idle. This may point to fuel being how the engine speed is being limited.
14.2 volts is good on the alternator, 14.4 or 14.5 would be as high as I would like to go. Anywhere over 13.8 or 13.9 with engine running is good. 12.6 with engine off is perfect, but static voltage with engine off is not a good way to check batteries though.
Honestly, i would check the coolant temp sensor first. Ford pickups had a big problem with this with no-starts when hot. It’ll start up cold great, even better than usual some may say. Runs good for the most part. But just wont start when hot, crank crank crank.
Well, when temp sensors fail they go full hot or full cold, just how it works, 0v is one way and system voltage is the other way. So whether it fails open (0v) or shorted (5v) its reading will be -40F or 250F. It seems to be running good when cold bad when hot, it’s usually the other way around. So these are good clues and I bet it can be fixed.
It would be nice to have that OBD data. Do you have a check engine light? Does it come on at all, like with key on engine off? Can you check for OBD codes?
I have no engine light and my attempts at reading from the OBD port have thus far been useless. No luck there.
I got my belts all changed when I first got the car.
PTU has been replaced so my tach being broken must be that actual dash, which I haven’t researched heavily to see if it is fixable.
I could jack in to the PTU tach wire and grab a voltage I guess, would just need to figure out how to convert said voltage to a rpm.
I would like to try to adjust my idle, but have been kind of scared to try since I see so many people saying not to adjust it from factory. Also not being able to see rpms to know where I’m adjusting it to is kind of sub par.
Coolant temp sensor would be sending data to the gauge on my dash would it not? Cause that gauge seems to be working fine which is why I never really thought of it.
There is more than 1 temp sensor. The dash reading comes from a different sensor to the one which talks to the ecu. It is the ecu one which may have a fault.
I need to be more clear somehow, yeah I’m not recommending adjusting the idle at all. Merely mentioning I would check it since it seems off. Same with the temp sensor, let me be clear, i’m not recommending throwing parts at anything. Typically they can be checked easy with an ohmmeter in a few minutes, if we can get to the connector that is. And even if we can’t find the specs of what it’s supposed to be, we could figure out if it’s good if we could get a reading.
The idle speed thing, part of me asking or thinking about checking it is i wonder what will happen when you enter that mode. From what i’ve read (i haven’t done it yet) when you enter that mode the computer is designed to go to a specific rpm and hold, and allow for adjustment. Well, my thinking was, will the engine speed up as soon as it goes into this mode? That would illustrate the computer controls are responsible for your low idle, because the car is capable of doing whatever it’s told.
Conversely, if the car is supposed to be idling higher than it is and the procedure clearly states it should be X rpm but your car is under that, then that’s a major clue the computer controls are not able to overcome something on the work side. If that makes sense?
I’m sorry I don’t really know how to help except to dream up what could be possible and dream up things to test and what not. With no OBD data whatsoever it’s old school diagnosis and these are complicated cars, it’ll take time.
I have a cheap timing light that shows rpm. ~$50 US. Lex has been pointing out to people there are affordable phototachs out there, that’s a cool option too.
I didn’t know there was more than one coolant temp sensor and that’s very good info to know. Having videos like Joe’s electronic module videos are super helpful with these cars, I believe there’s a bright side to everything, and if you’re intent on fixing your car that bright side is you’re about to become much more familiar with it. And that always makes things so much easier next time.
Edit - for me, personally, I wouldn’t be satisfied with the OBD side of things until i had a resolution. I’ve seen cars where the CEL bulb is burned out and doesn’t display with key-on engine-off so they never knew they had a light (you sound too savvy for that). But on the modern cars there is a power wire that supplies the DLC and it’s very common in American cars for that wire to be common with the cigarette lighter power wire – and the fuse is commonly blown. This is usually discovered by someone trying to pull OBD2 codes and there is no comm with the vehicle. If it were me, i would pursue that fork until I get the “all clear” gauge sweep on an analog voltmeter as per the OBD1 instructions.
I was also questioning the CEL at one point so I unplugged the MAF and the light turned on, I checked the code and it was pointing to the MAF (it was actually the 3 different sensors in the MAF). Plugged it back in and I got the all clear signal.
The reason I’m thinking about just turning up the idle is that if I do, and the problem persists, then it is surely a sensor fault I would think. If it fixes it then whooptydoo!
I’m definitely learning a ton, Joe’s videos have been massively helpful in both trying to troubleshoot this particular issue as well as the dozens of other small things on the car, inside and out.
My current thinking is that I’ll need to eliminate this belt squeal/squeaking first just to get one more variable out of the equation. Then I’ll go after my tach to see if I can either fix my current one or get a timing light as you were saying. Once I’ve got a tach reading I’m thinking that turning up my idle by just a little bit will shed quite a bit more light on the root cause of the issue. In the meantime I’ll be sending it to the shop to get it aligned, and I’ll ask them to check idle fuel pressure and replace fuel filter while its there.
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Oh, that’s much different than I thought, great job at testing the CEL and getting a resolution on the OBD side.
You know, all of a sudden I’m doubting the coolant temp sensor now because surely that would be monitored and set a light, even on a 91. But I would still check it and check everything, because something is wrong and these early OBD systems were minimal at best.
Good stuff, you sound heads up and seem to have a good plan. Keep us posted please
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Delayed update here but better late than never I guess.
I had a mechanic take a look at it and he just adjusted the idle up “just a little bit” and now the car runs just fine. My mechanic told me it looked like someone had messed with it, and I know I didn’t touch it, so safe to say the previous owner was getting a little handsy when he shouldn’t have been.
At any rate, thanks to everyone who tossed some advice my way!
On to fix some other issues!
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