95 Tahoe hard starting, then runs OK

[Gregb1954]

She can be very hard to start when cold. Then once started runs fine, although it may be running rich (or maybe its just blowing all of the gas out of the engine...). Also, once the engine is warmed up, it starts just fine.

Any ideas?​

 

[MO Viet Vet]

Sounds like fuel system is bleeding done after shut off and it has to re-prime itself to start again. When warmed up and shut off for a short time then it is still primed enough to restart quicker. Could be a bleed off at injector or check valve in the pump. Any check engine lights and/or recent work?

 

[Gregb1954]

Hi Raiderron.

No recent work and no codes. What you say makes sense. How can I confirm either of these possible conditions exist? If I use starting fuel (ether) I suppose that would confirm the absence of fuel at the beginning of engine cranking?

 

[MO Viet Vet]

Attach fuel pressure gauge and start the engine and then shut off and see if the pressure drops and how quick.

 

[Gregb1954]

OK, I will get hold of a pressure gauge and see if there is a drop. Great idea, thx!

 

[MO Viet Vet]

Post what the fuel pressure is with key on engine off, watch and post the number that it goes to while cranking the engine, once the engine is running post that pressure and then, as I said, shut off and watch to see if pressure holds or bleeds off and how quick.

 

[lesterl]

95 will be TBI, no pressure test port, Hard start when cold is What exactly, like have to crank 10x and 30seconds each or just longer start?

Might check the Coolant temperature sensor and its connector to make shure that it is reading right it can make a very hard cold start.

Also might check battery voltage before cold crank, and maybe try a cold crank with a jumpstart to see if it helps. Fuel pump issues can be helped with this also and also by cycling the key before crank.

Does the engine turn over slower when cold? Timing?

 

[MO Viet Vet]

Sorry, forgot to mention will have to install the gauge inline with the fuel line. If I remember right you can unplug the coolant temp sensor and see if that changes the starting problem. It is like the choke for the fuel injection system. Good call lesterl.

 

[lesterl]

Unplugging CTS will show -40* and will flood the engine, selecting a resistor instead in the range of 2.5-3k will show near 70* temps. and allow a leaner start than just leaving it unplugged (unplug sensor, stick resistor leads into wire side plug holes).

http://www.tahoeforum.com/attachment.php?attachmentid=6813&d=1388890284

 

[MO Viet Vet]

LOL! Or that.

 

[MO Viet Vet]

I gotta say lesterl. I have never seen a coolant temp sensor cause the long crank before start problem. Not saying it can't happen, just never seen it. I can see how it will cause a rich condition and if bad enough maybe the plugs get fouled and that is the long crank before start source. I am interested now in what fixes this for sure. How is the weather in Mo. lesterl? Just wet and rainy here and about 45-50 degrees.

 

[lesterl]

Was near 70 today..... Gonna be below freezing tomorrow..... gotta love MO.... Dry for now....

Have had issues with CTS on TBI's, also TBI base gaskets and EGR valves.... Resistor trick will cause them to fire right off if it is bad....

 

[MO Viet Vet]

Well I hope he tries it and it works.

 

[bptahoe]

I had a nearly identical situation a while back, and had not codes. Got harder and harder to start, but was fine once running. Everything checked out fine...initially. After much time and frustration and money...it was a faulty non-OEM rotor that was cross-firing. It got progressively worse and finally wouldn't start. I know it seems odd, but it explained why I had fuel and spark but it wouldn't run because spark was at the wrong time. It wound up costing me the spider because I let the thing sit for too long. Just thought I'd mention what my experience was...it was puzzling.

 

[lesterl]

Good point, aftermarket Igntion crap.......

 

[adam74]

I have the same problem with my 95. motor turns over normal just takes a couple 2-3 second cranks to start it if the motor is cold whether its 40 or 80 degrees outside. once motor is warm starts right up. I don't have an ac delco cap and rotor on it so I'll give that a shot in the near future. do have a new coolant temp sensor ac delco plugs/wires, ac delco egr valve

 

[lesterl]

New fuel pump, NGK plugs, AC Cap/Rotor and wires and mine fired up good...... Kinda miss that old rig..... was easy to work on....

 

[Nurser]

I had the same problem. Changed the Spider Injector out, boom. Fixed. It was a five hour job, but it solved my problem.

 

[lesterl]

95 has TBI injector not Spider (CSFI) injector......