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Username Post: 1995 Suburban crank hard start/no start        (Topic#357731)
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-19-19 04:20 PM - Post#2773604    

Hi all,

I’ve been having an issue recently in that the engine will crank and start from a cold start but it takes 4 or 5 attempts to get it to fire and stay running. I always wind up giving it gas by stepping on the accelerator but I’m not sure if that’s actually helping or it’s co-incidental.

Once it’s going it runs ok and you can drive where you want to go but if you stop anywhere, It will not start again until enough time has passed, (about 3 hours?) presumably for it to cool down.

It also has a tendency to stall from standing starts (no matter if it’s warmed to operating temp or not) and if that happens it will not start until enough time has passed.
This is what I checked so far:

Check Engine Light = NOT on. No codes just repeated ‘12’ (using Paper Clip method)
Vacuum good = 19”Hg steady

Air Filter = Removing Air Filter did not help

FUEL:

Fuel Pressure when running = 11psi steady

Fuel Pressure when key in start POS engine off = 11 psi (drops back to zero when Fuel Pump stops)

Fuel Pressure Regulator = Visual inspection revealed Diaphragm not leaking, spring strong?, not broken.

Fuel Filter = N/A removed for testing

Gas Cap = Removing Gas Cap did not help

Pouring Fuel down TB throat did not help

Spraying Starting Fluid down TB throat did not help

ELECTRICAL

Alternator = Putting out 13v/14v to the battery
Battery = New (Replaced after issue start. previous battery was 1000 CCA)
Cables = Good
Starter = New (Replaced after issue start. 12.4 v getting to Starter B+ from Batt)
IGN Switch = Bypassing with remote starter did not help

Neutral Safety Switch = bypassing with remote starter switch did not help
Spark Plugs = Tanish colour. seem OK (Removed two random plugs)(will check with OTC HEI Spark Tester as soon as I acquire one)
OTHER:
MAP = disconnecting electric connector to MAP did not help
EGR (unplugging vac to EGR did not help. NOTE there was no vac coming from square black unit just ahead of EGR but the black unit has Vac going TO it.)

Any help would be greatly appreciated!

Cheers!

Tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3837
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
08-20-19 05:01 AM - Post#2773636    
    In response to tonyfalcon

Welcome to the board!

It sounds like heat could be causing the ignition module in the distributor to break down. Many auto parts stores in my area will test the distributor module for free if you bring it in.

The test results from these stores are not always accurate, and some times the will say the module is good when it is not, but for a free test that may find the problem it is worth a try.

Make sure when you install or reinstall the distributor module that you use heat sink compound under it. The compound helps dissipate heat from the module. Without it, the module will fail.

Look very carefully at the terminals on the connectors that plug onto the distributor module. Make sure they are not corroded and the fit tight (wire terminals not stretched open).

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-20-19 06:58 AM - Post#2773653    
    In response to Chevytech

Thank you very much,

I was planning on testing the ICM myself if it was
intimated so now that you mentioned it i will do that. Just need an LED light and HEI Spark Tester.

https://easyautodiagnosti cs.com/gm/4.3L-5.0L-5.7L/...

What do you think about the possibility of a bad TPS or CTS?

Cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3837
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
08-20-19 07:28 AM - Post#2773662    
    In response to tonyfalcon

You're welcome.

A TPS voltage showing wide open throttle will put the system in the cleared flood mode cutting fuel delivery, BUT pouring fuel in the TBI did not help so that should not be the problem.

The most common failure for the CTS is reading to cold which would cause to much fuel to be injected, and sometimes so much it will cause flooding.

When it won't start see if the injectors are squiring fuel, and check to see if it has good hot spark.

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


Edited by Chevytech on 08-20-19 07:29 AM. Reason for edit: Spelling error

 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-20-19 11:48 AM - Post#2773685    
    In response to Chevytech

OK thanks again,

OK will look for fuel squirting from Injectors while cranking and attempting to start. Should be easy to create a crank-no start condition.

Will also run the test for the ICM now i have an LED test light.

cheers!

tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3837
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
08-20-19 01:11 PM - Post#2773689    
    In response to tonyfalcon

There are multiple ways the ignition module in the distributor can fail.

The module can fail so the coil no longer produces spark.

The module can control the coil and produce a hot spark but not send a reference pulse to the computer so then the computer does not trigger the fuel injectors.

The module can fail so the the computer gets a reference pulse and the injectors trigger and produce spark, but the spark produced is weak because the field collapses to slow ( like a failed condenser in the old distributor with points).

If the pickup coil in the distributor fails there will be no spark and the injectors will not trigger. The module can fail causing this same outcome.

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-20-19 07:29 PM - Post#2773721    
    In response to Chevytech

OK many thanks!

I ran the tests 5, 6 and 7 (as described in the link I posted earlier) and unless my tests are erroneous I verified that the ICM is not sending a switching signal but IS receiving the Pick Up Coils signal which would indicate that the ICM is BAD.

I'll take it to Autozone for testing tomorrow and if they concur i think we can safely assume i need a new ICM.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-21-19 11:02 AM - Post#2773766    
    In response to tonyfalcon

ICM tested good at Autozone.

I guess my test for the Switching Signal at the coil was erroneous after all.

As soon as i get a HEI spark tester i'll check if there is spark to all plugs at the time of crank- no-start 'cos i actually don't know the answer to that yet.

Still haven't checked that the injectors are squirting fuel at that time either. Will check later once i get the Dizzy back in.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-21-19 05:54 PM - Post#2773786    
    In response to tonyfalcon

OK the Injectors are squirting Fuel in bursts during the crank no start condition.

All i have to do to create a no-start condition is to start and run the engine for a minute and I guarantee it won't start again when i shut it down.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3837
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
08-22-19 03:10 AM - Post#2773800    
    In response to tonyfalcon

Because the injectors are squirting fuel we know the pickup coil in the distributor is triggering the module and the reference pulse from the module is making it to the computer.

You need to see if the ignition is producing a good hot blue spark. A weak spark may look orange.

A failing ignition module or ignition coil can cause a weak spark. Occasionally a coil wire will burn open on these trucks but the symptoms your truck is having don't seem to fit that failure..

When the engine starts the distributer module is in the base timing mode, but as the engine starts the module switches to electronic spark timing, and the timing is adjusted according to a signal it receives from the spark (knock sensor) module while in the electronic spark timing mode. The switch over happens around 400 to 450 RPM. When you can get the truck to start you can try unplugging the set timing connector and see if the module can switch back to the base timing mode and still produce spark. The set timing connector is inside the cab near the computer on a 1995 truck.

Just because the module passed the test at the store, it does not mean the module is good. Sometimes they pass until they are tested repeatedly to warm them up. See if it has a good hot blue spark when it won't start.



For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-22-19 08:04 AM - Post#2773808    
    In response to Chevytech

ok thanks again,

Unfortunately i have to work today and won't be home 'til about 1.0am but i will get on it tomorrow.

I should point that'cold start' has never been an issue yet. Sometimes it will fire up and run 1st attempt but after only 30 seconds of running if you turn it off it will not start.

It used to be that it would always start even after running but only after 4 or 5 attempts. Now it won't even start after running.

The ambient temps are in the 100's right now and the truck runs hot @ close to 210*, albeit fully loaded, driving 75mph on the freeway at 110* ambient so i don't know if that might have a bearing on the issue.

Anyway, tomorrow i will check the spark strength when cranking with no start and also see how it is with the Timing port unplugged

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
Bill K.b 
Senior Member
Posts: 4440

Loc: upstate NY
Reg: 10-24-05
08-23-19 02:22 AM - Post#2773857    
    In response to tonyfalcon

Nothing gets that hot in 30 seconds, though.

When you put that module back you replaced the grease on the bottom, right? That's important, it keeps it from getting too hot.


Those who can, do. Those who can't, criticize it on the internet.

Driving 2002 Express 2500
2002 Express 2500 extended
1988 G20 conversion
1993 GMC 3500 dually

Plus cars for swap and sale
& yes, I once tried a frame swap on a 51 Chevy.


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-23-19 10:37 AM - Post#2773886    
    In response to Bill K.b

Thanks

Yes you're right nothing gets that hot in 30 seconds so i'm thinking that would rule out heat being a factor when it enters the crank-no-start condition right?

Anyway, no i didn't put anything under the Module yet. Glad you reminded me of that.

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-23-19 09:22 PM - Post#2773928    
    In response to tonyfalcon

OK so the truck wouldn't start at all today which is the 1st time it's not started from a cold start. Battery @ 12.55v before attempting to start and i ran it down to 12.30v trying to start it.

I did attach the OTC Spark Tester to #3 cable while cranking not starting but i couldn't see any spark. I heard it but i couldn't see anything. I don't know if that was because of the bright sunlight or the Battery being too low or it's actually just not getting strong spark!

I didn't unplug the set timing connector yet 'cos i couldn't see where it was.

Got the Batt on charge now. Will try again tomorrow with a fully charged Battery.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
CowboyTrukr 
"8th Year" Silver Supporting Member
Posts: 4274
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
08-23-19 09:32 PM - Post#2773930    
    In response to tonyfalcon

Tony, the timing advance plug should be right behind the glove box liner. It’s a single tan/black wire with a connector that can be unplugged. It may be taped over.

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-24-19 11:11 AM - Post#2773956    
    In response to CowboyTrukr

OK thanks,

I'm just about to have a go at checking the spark again. I'll have a look for it...

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-24-19 12:30 PM - Post#2773962    
    In response to tonyfalcon

OK. Tried checking spark from #3 again and result was same. Spark was visible/audible but not very bright and was intermittent but THERE WAS SPARK

I don't think it looked yellow but I would call it a weak spark. However, I'm not quite sure what i’m looking for.

This time I grounded the Spark Tester by using a jumper cable to the Batt POS.

Also, had a look for the SET TIMING connector and I think I found and disconnected it. Well I disconnected a single tan/black wire going into a black connector. It was just to the left of the blower motor coming off a harness.

Unfortunately i don't have a very happy helper so I decided i’m just gonna buy a remote starter so I can do the rest of the test using that.
Shouldn’t matter for these tests right?

Cheers!
tonyfalcon



1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
CowboyTrukr 
"8th Year" Silver Supporting Member
Posts: 4274
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
08-24-19 07:42 PM - Post#2773983    
    In response to tonyfalcon

That’s the correct connector. You will throw a trouble code just for having it unplugged. Don’t worry about that one.

Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-25-19 03:03 PM - Post#2774034    
    In response to CowboyTrukr

OK thanks again,

I had seen a different description somewhere of where the SET TIMING connector was and it said it was where the 'carpet and heater box meet' so I was confused. I guess that's for a different year? Thanks for clearing that up!

Cheers!
tonyfalcon



1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
bowtie44s 
Valued Contributor
Posts: 4239
bowtie44s
Age: 36
Loc: wv
Reg: 08-29-12
08-26-19 07:01 AM - Post#2774062    
    In response to tonyfalcon

You don't need a fancy spark tester. I don't know how it works but I'm pretty sure you won't be able to see the actual spark that lights the air/fuel.

Hold the spark plug against a head bolt and have someone crank it. If you have a bright blue spark it's good. If you have no spark or orange spark you have a problem.

Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-26-19 04:39 PM - Post#2774103    
    In response to bowtie44s

Thanks,

Actually with the OTC 6589 Electronic Ignition Spark Tester you can see the actual spark and from what i've seen it's much more rapid and stronger than what I'm seeing at the spark boots i've tested.

I also checked the #3 and #6 towers on the Dizzy and the spark was weak and slow the same as @ the Spark Boots for those two.

I checked the spark directly at the coil and also the Coil wire and it fires rapid and strong.

All these tests were done with the SET TIMING connector unplugged.

So anyway i'm starting to think that the problem may be with the Distributor/Cap/Rotor.

cheers!
tonyfalcon



1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
CowboyTrukr 
"8th Year" Silver Supporting Member
Posts: 4274
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
08-26-19 06:36 PM - Post#2774124    
    In response to tonyfalcon

I don’t like spending other people’s money, but when it comes to a 24 year old distributor, if you’re at all considering spending money on that, I’d buy a new distributor. Just my take.



Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-26-19 09:01 PM - Post#2774137    
    In response to CowboyTrukr

Thanks,

I was leaning that way since a cap and rotor will cost $30 and if i wind up buying the whole Distributor it will come with a cap and rotor.

However, I'm still not entirely sure the Distributor is the issue.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
badbob85037 
Poster
Posts: 71

Loc: Arizona
Reg: 03-13-09
08-28-19 07:35 PM - Post#2774361    
    In response to tonyfalcon

I use to have the same problem. I went to a breaker point ignition. Something I have the knowledge and test equipment to fix.



Edited by badbob85037 on 08-28-19 07:44 PM. Reason for edit: No reason given.

 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
08-29-19 09:58 AM - Post#2774405    
    In response to badbob85037

OK so Now that i have the right test equipment i was able to run test#6 from the tutorial i've been following (see link in earlier post)which is the test to see if the Coil is receiving the switching signal from ICM and the LED Flashed as expected.

It would have had to otherwise the Coil wouldn't have anything but i wanted to see for myself anyway.

Anyway. That's were i'm at. The only thing i found so far is the spark from the Dizzy and spark cables appears WEAK in comparison to the Coil and Coil Wire.

Cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
09-17-19 09:01 PM - Post#2775770    
    In response to tonyfalcon

BTW just in case anyone is wondering, I haven't solved this issue yet. Just waiting for funds to become available for a new Distributor...

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
deckeda 
Poster
Posts: 79

Reg: 08-13-18
09-18-19 06:22 AM - Post#2775789    
    In response to tonyfalcon

I realize distributors are cheap these days (how?) and that it'll come with cap/rotor but if "that" fixes the problem it's just as likely it's because of the included module. Which is like $10. I've thrown far more than $10 away on worse ideas.

As noted above, it could have tested good in the store but still be bad.

That being said, if your truck has high miles the original distributor may have loosey goosey bearings or a worn gear drive.

I like buying cap/rotor separately so that I have a better idea of what I'm getting. Very happy with Standard Ignition Blue Streak, but that brand isn't the cheapest.

'89 C3500 dually 2WD, 4-sp (SM465)


 
tonyfalcon 
Poster
Posts: 17

Loc: Arizona
Reg: 08-19-19
09-20-19 09:44 PM - Post#2776024    
    In response to deckeda

OK thanks

Mmmmmm? Maybe start with an ICM then if that's not it, try the cap and rotor etc...

I guess my main reason for holding out is i kinda wanted one with a LLW which will mean getting a complete unit from Autozone or O Reily's or wherever which is around $140.

On the other hand i see complete distributors as low $60 as at Rock Auto and ICM's as low $10 so it's kinda tempting 'cos at least i'll be getting somewhere.

cheers!
tonyfalcon

1995 Chevy Suburban K1500
1965 Ford Falcon
1980 AMC Concord
1990 Geo Metro


 
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