Cantankerous 91 Storm

Okay, I give up, I surrender to the curse of the Storm.

Problem car is a 91 Storm, 1.6L, Auto, Non-Turbo.

Developed a hesitation, a real nasty one. It runs great until it is fully warmed up then it starts. It is only off the line. Once it is turning it runs ok. If you pull away from a traffic signal it may or may not move. You have to tease the pedal to get it going if it acts up.

Thinking it was the emissions system, and I still do, I went after it. It had an intermittant O2 sensor code, replaced that and replaced the map. Tried some parts swapping from a 90 Storm, long story on that one. Still hesitated. Even tried a distributor swap from the second storm.

Got a bargain on an Actron Sensor Checker. Double checked the new O2 and MAP. Both Good. Everything else checking good except the IAC. IAC shouldn't cause a hesitation, I think. Besides, the checker says its ng but it seems to be working ok.

During all this I had it running fine for about two weeks. Thinking the problem was maybe a non-ecm connected component I suspected the EGR. In checking that out the valve itself seemed ok. The Backpressure transducer tested bad. Put the alternate one in from the other Storm. For two weeks the thing ran great. Now we're hesitating again but, on the other hand, the egr seems fine now.

I am going to take one more look at the emissions components next. I
better also check the wiring to the ecm from all sensors. It really seems to be emissions related. Again, it runs great before it is fully warmed up. Also, if I disconnect the MAP after it is warm it runs better, not great, but much better.

Have I missed something obvious in all this? Have I missed something not so obvious? Could it be the IAC after all? I am actually going to have to pay a pro to diagnose this thing if I can't get it to behave. That's terrible :)

Replace the IAC......it could be your problem....I am dealing with the EXACT same issues. I have a straight pipe exaust. I have replaced damn near everything.
IAC
TPS
CTS
every vacuum line
Cleaned the fuel injectors by hand
Cleaned out the intake
Fuel filter
Ignition Mod
pick up coil
ignition coil
plug wires
plugs
checked compression 190/200/175/200
Oil is clean not milky
not blowing smoke
plugs are clean
Checked MAP
distributor cap
checked timing
swore alot
curse a few times
kicked the car
please let me know how your turns out. The only code I got was 14 or something....coolant temp sensor. I replaced it.

Hey YKM thanks for the reply. Sorry to hear you are having the same trouble but misery loves company:)

This is really a total pain. I put two kids through college ang get all set to buy two new cars when I was let go by my employer along with thousands of others. They refer to it as a "force management plan" My reaction to it would violate the rules of the newsgroup I am sure.

Anyway, the stupid Geo has been very entertaining since mid winter. It first blew a head gasket. Some hundreds of dollars and some cussing and screaming and I fixed that. It ran really well for some months now this, this, insanity that we both seem to be facing.

The IAC might do this but I doubt it. In any case I tried the IAC from the blown Storm I have sitting here. It changed not at all. I think it's unlikely that both IAC s would cause exactly the same symptoms. On the other hand they both test badly. The sensor testor can't move the pintle in or out. But, if I deliberately retract it and start the car the ECM is able to reduce idle speed. It must be doing it by extending the pintle. Therefore, the thing may be working. On the third hand, though, it could be working but too slowly. This is really NUTS!

I have done much of what you have done. Add a new MAP. I was trying the one from the other Storm when I dropped the original one. Never did find the thing.

For a while I was on the EGR system. Even bought a new transducer. That all seems to be a dead end. It helped a little but not much.

The computer issues no codes at this point. The only one I ever got was for the O2 Sensor. Replaced that and all went well after that.

I have discovered one thing in the last few days. I know the engine temp sender is good but in rechecking it for the seventy-fifth time I found one odd thing. If you disconnect it, pull the plug, no code. If you short the connector it does light the mil. The disconnect should light the mil.

There are three explanations for this. The first, it's normal. I checked that. It ain't. The second is the computer has gone completely mad. Everything else is ok so maybe not. That leaves a wiring problem. I have thought about nothing else for the last couple of days. It would do this only is there is a partial connection between the two leads to the sensor. The computer would get a false reading but it might now be off enough to set a code. Sooooo-under the dash for me. It looks like a stinker under there. I guess I am going to find out how hard it is to lower the ECM.

If you made it this far, thanks for listening, I'll let you know what happens. I am probably going to look at the thing on Thursday..

By the way, here's another wierd bunch of stuff. The cars in the house seem to catch things from each other as if they were diseases. The head gasket thing happened to my kids Storm that i now use as a parts farm. It can't be anything I am doing as he was paying a mechanic for maint. on that one. Also, I have an 86 Camaro that was a toy for me. I am trying to use it for transportation due to the layoff thing. That beasty has a nasty emissions problem. I have spent a fortune on it and still can't get it through inspection. I'll stay off that subject for fear of boring you to death:) Besides it really belongs in another forum.

In the words of the Governator-I'll be back.

Well I am working with a few variables.....
1) the engine block is brand new 1200 miles
2) the head is about 32,000 miles
3) the ECM is 162,000 miles
I was able to keep the car from stalling for awhile by pulling the Coolant Temp Sensor CTS.....it idled higher but idled steady....for awhile then just cut out. I didn't get any type of warning, and the car would not restart. I plugged it back in....vrooomm!! And back to the stalling.
Today was the best it has run in months....after I cleaned the fuel injectors. I found some nasties.
I may have bad gas....I have gotten some OK results from running a witches brew of high octane/fuel additives/fuel injector cleaner/water removers.....but the problem keeps coming back. I had filled up a full tank....ran for a 1/4 tank and then the stalling started. I parked the car and drove my SHO for a few months till the Transmission went on that. I will have to sell it shortly due to when it died I lost my job cuz I needed a nice car for work.
I am leaning to the idea that my head is bad on the Storm.....this head has blown 2 head gaskets last summer. Both times due to over heating. I checked for a warped head and it was WELL within the specs given by the Haynes manual I am using.
I was running my witches brew and all was well on the freeway.....doing a nice smooth 90 mph and suddenly the temp gauges shot thru the roof! I slapped it into nutral and coasted for about 1 3/4 miles....popped the hood...I had coolant all over the engine bay. It took some looking to find the problem....I blew out a freeze plug. The little tiny one at the 1:30 position in relation to the oil filter on the back of the engine near the Alt. I nursed the car home stopping every few blocks to dump in coolant and water. The temp gauge I installed read the block at well over 250+.....The head gauge read at or below the red mark.
Keep in mind that all this was long after the Hesitation/stalling began so its not related.
Aslo of note.....the car has been overheating. I have a good water pump and new raditator. I pulled the thermostat and started to run without it for a while. I will get poor gas milage...but I want to get rid of the gas anyway.
Another test I ran one day was looking for a vacuum leak....I took a torch and let the gas seep out all along the intake and hoses.....I didn't get any reving or changing idle.
As this car has become my daily driver.....I need to fix this stalling stuff.
I am not as knowledgeable about testing the wiring. I have a decent tester and can follow some instructions but my tester has too many settings and I never know what one to put it on. the ECM swap shouldn't be too hard from what I understand. I have never done it but let me know if that solves your problem.....I know a junk yard who gives me good deals.
Malachi
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Hmmmm-Overheating, rough idle and blowing head gaskets.

I'd be real careful about this as you could wind up spending dollars and not fix it. But an internal water leak could be going on. If there is something going on with the head enough coolant could be getting in to rough up the idle but not steam enough to see it easily. Our Storm actually was running funny for some weeks just before the head gasket blew. If you think it'll help and you can hustle up a pressure test for the cooling system you could check that out easily. The problem is the darn testers run about $100. I'd be real careful about making sure it has the right adapter for the radiator on that car. You could pay to have the test done. Probably an hour of labor or less and its done. Of course you'd have to have someone that cooperates with a driveway mechanic. If it turns out to be a leak I would have a shop do a check and deck on the head. They run about $100 at least that's the rate in NJ.

My Storm will be attacked on Thursday. I am going to check the wiring from the CTS to the ECM first. If that's ok I guess I need to verify that business with the MIL not coming on when the sender is unplugged. If that's not normal the ECM is sick. Then I have a choice of getting it flashed or trying a junk unit. The problem with the computer in these cars is that they don't use pre-programmed chip. They have to be set up by someone with the correct equipment if they act up. Yuk!

If I try to use a junk it would have to be from exactly the same model, year and equipment load. The computer from my second Storm won't work on a quick swap basis. It has a five speed and is one year older. I think the five speed would be a problem. I guess I'd try it before I spend any money on the thing though.

Oh yeah, again real strange, my Camaro also has an ECM problem. It appears to have the wrong chip in it for the car. I think it's a factory defect that didn't cause as severe a problem under our old state emissions testing but now--!@#%$$!

Anyway, I look forward to Thursday's effort. Sorta like looking forward to having a root canal done :) I like this stuff when it's hobby work. When it's a necessity it really stinks.

Well I am off to check two new avenues....I did a compression test a few weeks ago....I will re-do the test and see what I get
Last time was 190/200/175/200.
The other avenue I am following....and this seems highly likely.....leaking head gasket...leaking compression INTO the coolant.
I was given this direction as I get problems of a blown head gasket....but not the symptoms (milky oil...ect.)
The only way I know of is to check for air bubbles coming up after the car has warmed up. Either in the radiator or overflow bottle.
I checked earlier today and I got a steady bubble stream into the overflow.....this is why I am doing another compression check.
I am also going to play with my timing. I have never set the distributor on perfect as I don't own a timing light. I will try and get one...or play with it.
Malachi

That all fits with my thinking also. Bubbles and overflow can indicate a compression leak into the cooling system.

You are getting much more cranking pressure than I get. Then again your engine is new so it should do well. Mine is totally even but only gets about 125 on all cylinders. On the other hand is close to 200 lbs normal?

Setting timing on this car is real easy but you need a light to do it accurately. The distributor is very easy to get at and adjust following the grounding procedure to eliminate the ecm.

Anyway, good luck with your next step. Mine comes tommorrow.

I hope your project is going well.....
I went out his morning....tried to fire it up....wouldn't start....I checked for spark....ok
Pulled the plugs..........lots of gas on them....what the heck???
I had to turn my Distributor as far as I could clockwise to get it to start up....very odd....I willl have to check my timing marks but the belt looks ok and not damaged.....I also checked it for tension and it was plenty tight enough.
So I reran my compression check.....using a different gauge
Results from before:
200/175/200/190 with engine hot
new results
161/182/179/185 with engine cold
179/182/182/186 with engine hot*
* very consistent
Stock compression on a SOHC Storm should be at 159lbs
I am not sure what all this means.
I also re-did the coolant check for air bubbles....I took off the cap with the engine hot....I was told I would see hundreds or even thousands of bubbles.
I saw what can only be measued in dozens???
I will have to redo the test again to see what happens.
Have you made any progress?
Malachi

Hey Malachi-
Sounds like fun. I would agree on that timing belt check. If it jumped for any reason it could cause all kinds of things. The way the distributors mount you might be able to put it in 180 degrees off but you would have noticed that. The only other thing that could send the timing out of wack would be the plug wires in the wrong holes or maybe a problem with the ignition module in the distributor.

The bubble thing-I have seen it where you leave the cap off and warm it up. Rev it then a little and you'll get all kinds of bubbles, maybe steam and some overflow. That is if its real bad. Otherwise, who knows. If all else fails I'd try getting a cooling system pressure test somehow.

That compression leaves me puzzled. Years back you'd get some very high readings from carbon build up. That was back in the dark ages when we had leaded gasoline. Besides, its a little high but not outrageous, I think :)

My situation hasn't changed much. I did take an extra cts and connected it to the lead on the engine. Then I left it laying against the block. It's reading mostly air temp. Ran almost right that way. I still think I need to check the leads to the ECM. If there is a partial short between the two wires it would cause the ecm to think the engine is hotter than it is. I postponed getting the wire check done in favor of some errands I had to run as long as the old beast was running better. Probably I'll do it over the weekend.

Melachi

I won-It seems very good now except maybe, and I do mean maybe, a little sluggish. I'll check the timing on that one.

The hesitation was caused by a bad cts. Talk about wierd. This was the first thing I suspected. I first used a good multimeter on it. The readings hot and cold appeared normal.Then I used an actron sensor testor on it. Again, good.

Next, I tried another cts from my second, dead, Storm. Still hesitated. This sensor also tested good.

In the end I decided to try a sensor, on a hunch, before I started checking the ECM wiring for problems. I bought a new one this time. It worked fine. Really an annoying bunch of nonsense this has been.

Next time I'll play my hunch first. I would have saved some money and some aggravation. By the way, the old sensors may simply not have been getting a decent ground. Not sure about all that. At this point I don't even care. Now I can start moving the better interior and other stuff from the junk Storm into the running one. The junker has many less miles on it than the running car.

How's your problem going? Any luck in finding out if you have that internal leak?

Ted

Well....after much work and all for naught I got it down to bubbles in the radiator=blown/bad head gasket.
I got a new head gasket and took my time over two days and did that....
I don't have timing light so I just put the Distributor on in the middle and pray everytime...darn thing ALWAYS starts.
Car runs THE SAME!!!
it runs fine some times and others it runs like crap. It tends to run worse with higher temps and I get more stalling. This points to a bad ignition mod. still so I took an extra I had to the local parts place and they tested it and it came up good. I will try that in the morning....I am pretty sure I swapped it out already....I remeber taking it all apart to do it....but maybe I mixed them up and put a bad one back on.
The car runs fine on the freeway and when it is cold ....just in the stop and go stuff does it stall out.
I may look into grounding out my CTS also....I used RTV sealer to coat the threads when I installed it....I prefer to use teflon tape but I was out. It may not be getting a good ground.
The only code I ever got was CTS.
I am really starting to hate this car.........So far I have dumoped well over $5,000 into parts and stuff for this car....now some of this money was common everyday stuff like oil/struts/plugs.....but I am so wanting to give up.
I am VERY glad you fixed your problem. I hope it holds up.
Any advice you could give me would be apreciated.....
Malachi

Malachi-

Sorry to hear about your continued problems. I hate to ask this one. Did the bubbles go away? If not, did you have a deck and check done on the head by a machine shop? They plane them flat then pressure test it. If you have any more trouble with it I would invest the money and get it done. If there is any warp in it that you don't see it will keep blowing gaskets. It also could have a leak somewhere that you don't see. If you can suffer with it for a bit you can see if it uses any coolant.

If it isn't a continuation of the water thing and it runs fine cold then I would still be suspicious of the emissions system. The ecm in these OBD1 cars isn't all that good at spotting problems. Something could be working well enough to fool it but not well enough to make it run right. I had two bad cts sensors get past the ecm, a sensor checker and an ohmeter. Rediculous. I finally prevailed by following my first hunch and replacing the CTS with a new one. Look out for the MAT sensor also. Maybe check that the egr is functioning normally. You can see if it is opening and closing when you accelerate the engine. It should open when the engine is warm and accelerting to around 1500-2K.

I also just took another look at the diagram for the CTS. The ground is supplied through the harness from the ecm. It has two leads. One is for the 5v signal. The second is for the ground. Based on that the connection to the block may not be important. Am I absolutely sure? For my own purposes I would be but I am not a trained mechanic and could be wrong about anything.

I hope any of this blabble helps. In any case good luck with this. Let us know how it goes.

Well Ted.....I finally got it.....
The ECU was cooked.
I went to the junk yard and swapped in another one....car runs fine now....no stalling spitting or sputtering.
It has alot more power and seems ok!
Thanks for all the advice.
I hope your is still ok.
Malachi

Good work Malachi. It sounds like you won.

Since I did the last repair, a new CTS it has been running I guess almost right. It seems a little sluggish and I have been meaning to get to rechecking timing just in case. With the air on it really gets dog slow. It normally loads the poor little thing up but no like this. I think I could outrun it in a drag race with my old ten speed bike.

In any case all that wasn't bothering me too much as with the air off it has been ok.

Then, yesterday, it was hot as blazes and I had to run an errand about fifteen miles away. This was right after I put a new thermostat in as it had run hot the last time out. No overheating just a little too hot. In any case as soon as the engine warmed up the old nasty hesitation was back with a vengance. I was going to take it home as it was that bad. The only problem was that it was so bad I was concerned it wouldn't even make it the two or three miles to get there.

Anyway, I open the hood, don't ask me why. I guess to look like I was doing something for my wife's benefit. :) All I did was fiddle with the wiring harness near the thermostat as that was all that got touched recently. Then I restart it and the !$# runs as well as it has lately. This may turn out to be a wiring problem after all. That would explain much of what has happened lately.

In any case my other half is using it right now so I can't look at it. I'll probably just swap out the harness section near the thermostat. That may finish this up. I don't really feel like getting under the dashboard and checking for excessive resistance between the sensors and the ecm.

Anyway, I'll get it done eventually. Good luck with your Storm.

Ted