Hard cold start / fuel delivery problem...any ideas??

[tsi1991awd]

I have been having this hard start problem for a while now...when the engine's cold, it wouldn't start. It'd keep cranking forever. Lately it's been cranking for 15 minutes or more before it would start. Today I replaced the caps in the ECU. The old ones weren't bad, looks like they were fairly new and there were no burn marks at all. I changed the caps anyways.

That didn't help. I checked the resistance at the CTS and it was reading right. The car kept cranking at this point. The ECU caps didn't help.

So I took the plugs out, sprayed carb cleaner in each cylinder and put the plugs back in. Car fired right up!! So I now know that my hard start is because of a fuel delivery problem.

I am assuming since this only happens when the car is sitting for 8+ hours, the pressure in the fuel line is getting released somehow. I want to know where I should start?? Fuel pump? FPR? I'm planning on putting in a Walbro 255hp and AFPR anyways, but would these two things be the main source of my problem?

I've already changed the fuel filter at the beginning of October. The CTS is in working order. The ECU caps have been replaced. New spark plugs. New alternator. Battery is good. As I said, today it just cranked as usual. I sprayed carb cleaner into the cylinders and it fired right up, which makes me think the pressure is being lost somehow or.....???

 

[andy4g63]

Change the fuel filter and make sure your fuel pump is good.

 

[eclipsh]

See if you can get a hold of a fuel pressure gauge. My mechanic has one that can screw in to replace the banjo bolt at the fuel filter. See what kind of pressure you are getting. My FPR bleeds the pressure off pretty much instantly on shut off but it builds back up right away when I crank it over.

Issue # 2: Are you parking outside when this happens and is there a chance you have water freezing in your lines? How old is your gas?

Also, how is the voltage back at your fuel pump once it is running? You should be seeing close to the full current you read at the battery.

 

[tsi1991awd]

Change the fuel filter and make sure your fuel pump is good.

I've already changed it at the beginning of October.

See if you can get a hold of a fuel pressure gauge. My mechanic has one that can screw in to replace the banjo bolt at the fuel filter. See what kind of pressure you are getting. My FPR bleeds the pressure off pretty much instantly on shut off but it builds back up right away when I crank it over.

Issue # 2: Are you parking outside when this happens and is there a chance you have water freezing in your lines? How old is your gas?

Also, how is the voltage back at your fuel pump once it is running? You should be seeing close to the full current you read at the battery.

I'm not sure on the pressure, I'll have to see if I can get a gauge. I'm going to get an AFPR but it's going to have to wait for a little bit. I thought the line was supposed to hold pressure....?

And yea, I park outside...it doesn't necessarily have to be freezing outside for this to happen. Just as long as it's been sitting for 8+ hours and the motor is cold. So I don't think the lines are freezing....gas I just put in 4 days ago. I ran seafoam through the tank and it didn't help. Ran injector cleaner a separate time and it didn't help.

How would I check the voltage at the pump? Which wire do I need to test? And should this be done when the car is in the "ON" position?

 

[4ced4g63]

Have somebody turn the key to the on position while you are by the fuel pump listening. It should run for a second or two to build the initial pressure for starting.

You could also take a fuel line off at the filter or fuel rail and have somebody cycle the key quickly to see if you are getting fuel to that point.

Hope this helps. Good luck.

 

[brownfinger]

I got a B&M FP guage from Extreme PSI for $30. It mounts on a drilled banjo-bolt (included in the kit) on top of the filter. It will help eliminate some of your guess work, and is cheaper than a proper diagnostic FP guage kit, and it will always be there for easy reference. I'm not sure yet if it is the ECU, the relay, or the wiring, but my '93 NT does NOT turn on the pump when you turn the key to "run" like it is supposed to. It doesn't turn on untill the engine is running. This makes for horrible 1st starts of the day. The engine is trying to run while the fuel rail is still priming. I don't know how much help my situation is to you, but the B&M guage should be of some help.
P.S.: My ECU is a rebuilt original. It was fixed by a Mitsu. dealer. They told me the MFI relay blew, and took out the computer. Maybe the computer blew and took out the relay? I started noticing the hard starts around that time. Either way, I'm going to get a different ECU and swap it out to see if that helps. If you have access to one, you might try the same.

 

[tsi1991awd]

When I put the key to the on position, I have the door open and try to hear the pump but I hear nothing. I'll try having someone else turn the ignition on and see if I hear it.

Today it just kept cranking so I just used the fuel pump check connector by the battery, let it run for a minute. Then tried firing it up....it cranked 3 or 4 times before it finally fired up.

So I'm not sure if it's the MPI relay or........
Maybe the fuel pump check valve is bad and it's not keeping pressure in the system?

I took a look at the FSM and it says if the fuel line doesn't hold pressure, it could be the check valve so replace the pump....and if the pressure is gradually released, it could be leaking injectors. Not sure what the deal is, maybe it's the pump I don't know.

 

[talon187]

I would try a new coolant temp sensor...mine did the same exact thing when i had just put a new one in 2 months before...i know you said its in working order but i honnestly think thats your issue mine did the EXACT same thing yours is doing

 

[tsi1991awd]

I would try a new coolant temp sensor...mine did the same exact thing when i had just put a new one in 2 months before...i know you said its in working order but i honnestly think thats your issue mine did the EXACT same thing yours is doing

I wouldn't see how that could be the problem. It's reading the proper resistance, so even if it were faulty, it'd still start up correctly because the engine would get the correct resistance.

 

[talon187]

Do you have a wideband?

 

[talon187]

heres another idea. dissconenct the coolant temp sensor and see if it changes if it doesnt well then you'll know....

 

[tsi1991awd]

Right now the car starts just fine....I'll go start it up and then unplug the sensor and try starting it. We'll see what happens.

I do not have a wideband.

 

[tsi1991awd]

I went out to the car, it has been sitting for about 4 hours and it started up fine on the first try. Unplugged the CTS and it started the same. After maybe 20 or 30 seconds, the CEL came on. Plugged it back in, started the car...no CEL. I think the CTS is just fine....?

 

[talonstalon]

i have a walbro 255 and when my car is cold you have to bump the keep 5 or 6 times to let the fuel get to the rail.....but i going to put a switch in mine so i can let it prime before i crank it

 

[HighPSI TSi Guy]

your info says you run DS-MAP, is this issue there with the MAF as well? If it only occurs on Speed Density, send me your BIN and I can probably fix it for you.

 

[Afroclipse]

i have a walbro 255 and when my car is cold you have to bump the keep 5 or 6 times to let the fuel get to the rail.....but i going to put a switch in mine so i can let it prime before i crank it

What does bump the keep mean.

 

[dsmfa9nutter]

Replace your water temp sensor. Both of them. I had the EXACT same problem, tried the same things, hell, I even thought the same thing (fuel rail not holding pressure, it's not supposed to hold pressure when car is off fyi). Replace the sensors ($35+$8 at autozone) and put in new plugs, your old set is fouled beyond being good.

 

[93'colttsi]

I am having the same issue but mine is with my 93 dodge colt with a 4g63 i swapped in.

It did the same thing with the 1.5L that i had in there before.

Leave it for more then 6- 8 hours and it will be hard to start. Have to crank and crank it forever before it actually starts up. Once it starts and warms up a bit it starts and runs perfectly.

Definalty a fuel delivery problem.


Somone said that there is a plastic cap that goes over the fuel pump that can crack and cause the pressure to bleed down and get air into the system causing the hard starts

Also the other day the temperture was around -20 deg. Celcuis and the car wouldn't start at all. just a few "blurps" and that was it.

 

[Eclipse37]

Could just be due to cold weather.

 

[93'colttsi]

It should still start

 

[dsmfa9nutter]

I am having the same issue but mine is with my 93 dodge colt with a 4g63 i swapped in.

It did the same thing with the 1.5L that i had in there before.

Leave it for more then 6- 8 hours and it will be hard to start. Have to crank and crank it forever before it actually starts up. Once it starts and warms up a bit it starts and runs perfectly.

Definalty a fuel delivery problem.


Somone said that there is a plastic cap that goes over the fuel pump that can crack and cause the pressure to bleed down and get air into the system causing the hard starts

Also the other day the temperture was around -20 deg. Celcuis and the car wouldn't start at all. just a few "blurps" and that was it.

Sounds exactly like a WATER TEMP SENSOR symptom.

 

[93'colttsi]

I have replaced my coolant temp sensor (2-wires) twice so far with other units. No change. I also tested the unit to make sure the resistance was within spec and it was good. I had this problem even with the stock 1.5L engine was in there which had different wiring harness/ecu/engine and the only thing that has remained unaltered is the fuel tank/lines. I did swap in a walbro 255 HP, but it still did this even with the stock colt fuel pump.

Also when I undo my gas cap, even after the car has been running there is no hissing noise from pressure escaping from the fuel tank. In my other colt (all stock) it hisses when i remove the gas cap and it starts up perfect even if its -40 degrees celcuis!

There must be a EVAP system leak somewhere in the fuel system causing it to loose pressure!

I have heard that you can use a smoke test by pushing smoke into the gas tank and looking for leaks where the smoke is coming out. I imaging that the smoke would not be able to make it into the pressure side lines from the fuel pump to the fuel filter/rail though.


Damnit this makes me soo frustrated! I have been chasing this problem for years and years now to no avail!

HELP DSM GURUS!

The best solution I have heard so far is that the o-ring in the fuel pump is pinched or one of the lines is cracked allowing the fuel pressure to bleed off.

Sometimes when the temperature is hot (like 30+ deg celcius) the car will start first try no problem. Its just when the temperature gets down to the freezing level or below it makes the car un-startable.

Also usually if there is a problem or a wiring issue with the coolant temp sensor it will throw a CEL. No CEL here.

 

[tsi1991awd]

The wiring at the plug for the CTS on my car was faulty. The insulation was pushed back and the bare wires were touching AT THE PLUG that connects to the sensor itself, causing a short. No CEL was thrown. If I DISCONNECTED the plug, CEL came on. Otherwise, no CEL. Check the wiring thoroughly. If it's bad, cut the plug off and put spade connectors on. My car starts perfectly every time now. We just had a big chill / 6 inches of snow come through, single digit temps and the car started on the first try every time. Also had a bad battery and leaking injectors which I replaced, but I believe the CTS wiring was a big culprit.

 

[93'colttsi]

Hrmmmm

Ill double check it again. But my car still wont start easy even on hot/warm days.


it will start easier on warmer days.... but still not like it should.