cold start issue HORRIBLE cold starts, SPFI 88 GL Dual Range

[YnotDIY]

Hey Ya'll - 

Posting here of course hoping someone can point me to something I haven't thought of yet related to my issue.

1) Basically it's getting very cold at night here in Michigan now and when I go to start the car in the morning it's pretty impossible for it to warm up (erratic idle, stumbling, stalling out) unless I stay out there and keep it alive with the gas pedal. Here's the thing though as soon as the car gets to operating temp, BAM smooth. Idle returns to normal and it's stays on no problem.

2) Car drives around okay, lacking power in 4th and 5th for sure can barely get it up to 70mph on the highway. Really falls flat in 5th. Also surging and bucking a bit on take off until I give it some gas then seems to smooth out.

 was throwing codes

11 - Crank Angle Sensor

21 - CTS

24 - IAC

31 - TPS

34 - EGR (this was the only code without green or white connectors plugged in)

51 - Neutral Switch Always ON

SO FAR I'VE CHANGED

CTS (2 used, didn't test resistance using water method)

TPS (3 used all seemed in spec)

IAC

Dizzy Body (that code 11 had me thinking dizzy)

MAF Sensor

Checked Fuel filter for flow (looks good)

Checked for Vacuum leaks (none showing up)

 

It seems to me like it's something related to how the engine reads temp since at least it idles once it's warmed up. Maybe the 2 CTS I tried are all bad. At some point I'm thinking we can't keep swapping 30+ year old parts out for 30+ year old parts and expect spoob to work, but what do ya'll think? Anywhere else I should be looking? Thanks ya'll 

Oh and HECK WINTER.

 

[GeneralDisorder]

Grounding problems. You don't get that many codes and still have the engine run if all those things are actually bad. Check the 5v reference from the ECU at the ECU plugs and at all the sensors, check the sensor ground pins, etc and check the resistance of the CTS, etc at the sensor and at the ECU.... clean all the grounds, etc. 

GD

[YnotDIY]

Thanks GD, I’ll get to reading now. 

[YnotDIY]

Is this 5v reference with key on only? I’m pretty bad with electrical stuff never had to get into it until now.

if someone could give me a quick run down that would be great. I know I’m askin’ a lot.

[DaveT]

5 v from the ecu would only be there with key in run.

[Dee2]

Quote

Here's the thing though as soon as the car gets to operating temp, BAM smooth. Idle returns to normal and it's stays on no problem.

I don't think a grounding problem would go away when the car warms up.   With so many codes it seems impossible to know what's happening.  I would clear all codes and start over. 

if you keep getting all codes I would suspect the ECU/ECU connections.  Otherwise see which codes persist and go from there.

Edited December 12, 2019 by Dee2

[YnotDIY]

3 hours ago, Dee2 said:

I don't think a grounding problem would go away when the car warms up.   With so many codes it seems impossible to know what's happening.  I would clear all codes and start over. 

if you keep getting all codes I would suspect the ECU/ECU connections.  Otherwise see which codes persist and go from there.

My check engine light is either out because of ECU issue or burned out completely (not showing in dash). I'm going to fix that tomorrow and re-set the ECU codes since that light is instrumental in knowing if I've cleared properly.

[YnotDIY]

4 hours ago, DaveT said:

5 v from the ecu would only be there with key in run.

 

8 hours ago, GeneralDisorder said:

Grounding problems. You don't get that many codes and still have the engine run if all those things are actually bad. Check the 5v reference from the ECU at the ECU plugs and at all the sensors, check the sensor ground pins, etc and check the resistance of the CTS, etc at the sensor and at the ECU.... clean all the grounds, etc. 

GD

I've was looking at a service manual today and checking out pin numbers and corresponding  sensors ect, but I didn't see how to check them. Is there anything on this in anyones FSM? Would I positive probe whatever number I'm checking and ground to body or use a ground off ecu side? If ECU side does it matter which one? Seems there are a few.

Ground Pins as listed in 89 service manual PDF (got it off here)
30
35
42
44
50
51

example - 
Pin 23 (water temp sensor) 
  *positive probe pin 23 and negative probe to car body ground or would I connect to a ground pin listed above?? 

[DaveT]

After checking / cleaning the engine grounds, battery terminals, etc.  I usually use the battery - or engine ground point.  Unless I started getting really odd results,  then I might check the ground pins on the ECU also.

 

My 1990 FSM is where I found the off engine CTS test.

[ferp420]

if you havent done a full tune up i would try that plugs wires cap rotor airfilter

the plugwires cause all kinds of havok when they fail causes misfires and other issues depending on were.the spark is bleading off to even alittle loss in power to the plugs makes it hard to start

the taking for ever to warm up probably due to the intake being cold the fuel can fall out of suspention as it moves though the intake manifold making it even harder to start and stay running till the coolant gets up to tempeture the throtle body can actualy freeze up so basicly untill that coolant is hot its not gona be happy but it shouldent die just idleing

also the intake before the air filter has a tiny opening and dosent flow well at high rpms so check to make sure its open and theres not a piece of something partialy blocking it

if you cant find the issue i found a msd ignition system make a great band aid for all issues ignition related

Edited December 13, 2019 by ferp420

[DaveT]

I just re read the line about "it runs fine once warm."    This points really hard at the CTS.

The off engine test for the CTS is pretty simple.  2 used 30 year old CTS is not a great way to rule them out as a problem.

[YnotDIY]

 @ferp420   - Changed air filter, dizzy body (I was worried about that code 11 crank angle sensor), dizzy cap / rotor (huge improvement in start up smoothness), plugs just changed, and I'm waiting on a wire set that I can pick up tomorrow. Thanks for the heads up about the small opening pre air filter. Appreciate that knowledge. I haven't looked into these MSD systems. are you running one?

 @DaveT Thanks for the info about the ground pins / testing ground. That CTS test is basically put it in water at X degrees and measure Resistance right? X degrees correlates to specific resistance. I completely agree with you about these 30 yr old parts. I was laughing at myself at the pick n pull in Michigan, in the heckin' snow, pulling a CTS from a Loyale that hadn't had a hood in who knows how long expecting that would solve my engine issues. The car side connector crumbled in my hands. I"ll be doing tests tomorrow.

[YnotDIY]

UPDATE - 

Noticed a wire backing out of the plug for my Fuel Injector (injector side) didn't think much of it. Maybe I could see 1/32 of bare wire. Since I've swapped so much stuff with no luck this was on my list today. Pulled injector with bad plug from engine (looked like crap inside the cover), swapped it for a much nicer looking used one (installed new o-rings on injector before install) plugged it in and fired the car up. Seems much much smoother now. 

so I'm thinking I found the cause of this bucking jerking (2), but I wont know about that cold start up issue until tomorrow once the car has sat overnight. 

However! Still lacking power in 3rd, 4th and 5th. Just doesn't have the pull that it did before these issues. Ground issue? I'll test tomorrow and report back.

[DaveT]

CTS Test - put the sensor in a pan with some water, on a stove top.   Use a thermometer and an ohm meter.

It took a while, looking through my FSMs and finding my old notes -
Water temp sensor ohms
14F   7000 - 11500
68F   2000-3000
122F 700-1000

Above are from the FSM.

Below are actual measurements. Done at 2 different times, compiled here. The 1990 unit was in a good running engine. The new dealer unit was bought locally, and I made the measurements before installing it to get the extra reference points.
                   measured ohms
temp  1990 used      new dealer unit
77F                                  2390
122F      1154                 1098
185F                                400
190F       454

One of the main things to watch for is that the readings are steady, or drifting as the temperature changes. If the reading is jumping up and down, that's a bad sensor. If it doesn't change smoothly. If it is WAY off it's not good.

Notice the readings for the 122 degrees. they are all a bit different. But they work. That amount of off spec isn't going to cause noticeable problems. While not technically in spec, it's close enough.

[ferp420]

10 hours ago, YnotDIY said:

 @ferp420   - Changed air filter, dizzy body (I was worried about that code 11 crank angle sensor), dizzy cap / rotor (huge improvement in start up smoothness), plugs just changed, and I'm waiting on a wire set that I can pick up tomorrow. Thanks for the heads up about the small opening pre air filter. Appreciate that knowledge. I haven't looked into these MSD systems. are you running one?

 

ya i have a procomp al6 multi spark discharge box it made a world of differance it makes up for the short comings in our ancient rigs and sometimes brings them back to stock power ratings

i have a video about installing it but i got all my information off this site its so simple its stupid and completely reversable even on the side of the road

were would that bad injector wire be you only have 1 fuel injector in the throtle body so if its not working its not running we might need pictures something sounds off do you have one of those multi port fuel injection units

[YnotDIY]

@ferp420 started today from a cold start and car is running great! I have an SPFI and the injector wire in question was backing out of the plug on the injector side, not body side. Barely noticeable unless I was searching for it (and I was). Swapped in a new injector and it's much much better now. No more horrible start ups. Now I just have to figure out this power issue. Running good, but still lacking power in 4th and 5th going up moderate hills.  Gonna check grounds and resistance for all plugs related to fuel/ignition.  Mainly checking CTS and MAF now that injector seems good. 

[Dee2]

Quote

Running good, but still lacking power in 4th and 5th going up moderate hills.

Most of these old cars have power problems.  You may benefit from doing a compression and vacuum test on that engine.

[YnotDIY]

@Dee2 Absolutely I agree.

[YnotDIY]

Cleaned engine grounds besides negative battery cable on trans. I couldn't get the heckin' nut off and the piece of metal it's attached to is bending all over the place when I put torque on the nut. I'll need an impact wrench to remove it. I changed plug wires for good measure. feels smoother, but no power gain.

Went through process of changing check engine light so it lights now (was burned out), then I cleared the stored codes on the ECU. Check engine light went out during this clearing procedure as is normal. Just ran through process of clearing codes in the 88 FSM.  Check engine light back on and all codes in post no.1 are still there. Not sure what's up. I'm going through checking all the sensors now. I'll post more later, but I did notice the resistance on my MAF plug (car side) is over 10x what is normal.

FSM states MAF Plug (car side) should not be more than 10ohms resistance. Mine was coming in around 100ohms.... yikes. everything else on the plug tested normal output though. Just high resistance.

I'll go through more sensors and plugs and post results here. I'm now searching for my power loss issue. Cold Start Issue seems to be solved (but it's also 40 degrees today, so who knows, haha)

 

Thanks for all the help so far.