Hard starting

[Redwookie]

Hey all I had a question maybe some of ya can give me some input on. So I've got an 89 k5 w/TBI problem is that it's hard starting. Doesn't matter if it is hot or cold still gotta crank it a few times to start her up. Brand new battery and starter. I'm thinking it's just a loss of fuel pressure or a bad sensor. Any ideas the most likely culprit as far as which sensor? Thx.

 

[dyeager535]

If this is the only problem/symptom: run 12V to the red wire hanging off the fuel pump relay connector. Start truck. Problem gone? Your fuel pump relay is dead if so. If you can hear the pump running when you turn the key to "run" after the truck has been sitting, then you don't need to do this test, since the pump is priming, and that's handled through the relay.

You typically also get better starts, if the relay is working, by turning the key to run, waiting a second, then starting it.

 

[Redwookie]

If this is the only problem/symptom: run 12V to the red wire hanging off the fuel pump relay connector. Start truck. Problem gone? Your fuel pump relay is dead if so. If you can hear the pump running when you turn the key to "run" after the truck has been sitting, then you don't need to do this test, since the pump is priming, and that's handled through the relay.

You typically also get better starts, if the relay is working, by turning the key to run, waiting a second, then starting it.

Hey thanks I'll give this a shot.

 

[Redwookie]

Well I don't think that was the prob. Turned the key to "on" and heard a click then a little hum coming from about where the pump is. hmmm. Went ahead and ran a jumper wire to check codes and nothing came up so I dunno maybe it's a fuel leak?

 

[dyeager535]

I guess I should ask the obvious...is this a hard start problem, or is it normal and you are used to another vehicle?

You mention jumper wire for codes, that's not what I meant, did you give the red wire off the relay 12V and try the start?

My TPI setup takes a bit longer to fire than newer vehicles I drive/have driven, but that's the way GM set it up.

Are there any posts about poor fuel pressure causing hard starts? With the engine doing this hot or cold, very unlikely it's the coolant temp sensor, thats almost universally a problem at either end of the spectrum, not both.

 

[Cricket]

When was the last time you changed your fuel filter?

 

[Redwookie]

Well haven't changed the fuel filter in a while. I guess that might be worth a shot.

 

[Redwookie]

I guess I should ask the obvious...is this a hard start problem, or is it normal and you are used to another vehicle?

You mention jumper wire for codes, that's not what I meant, did you give the red wire off the relay 12V and try the start?

My TPI setup takes a bit longer to fire than newer vehicles I drive/have driven, but that's the way GM set it up.

Are there any posts about poor fuel pressure causing hard starts? With the engine doing this hot or cold, very unlikely it's the coolant temp sensor, thats almost universally a problem at either end of the spectrum, not both.

In answer no I didn't try jumpering the fuel relay but you mentioned turning the key to on and listening. I heard a click that and faint hum coming from under the truck from about where the pump is so I was assuming this meant the fuel pump was priming ok. Is that not right? Should I still try the jumper?

 

[dyeager535]

If you are certain you can hear the pump, then yes teh relay is fine.

Fuel filter shouldn't need to be changed very often, but if it's blocked up, then it's going to cause problems. What brand by chance?

 

[Cricket]

Your best bet is to check your fuel pressure before changing out a bunch of parts.

When was the last time you tuned it up? I see you have a new battery and starter but what about the basics like spark plugs, cap & rotor, pcv, air filter.

 

[Redwookie]

Yep everything id new or at least less than 3 months old plugs, etc... I'm not sure what brand the fuel filter is. I think maybe I'll get my hands on a gauge and try checking the fuel line pressure.

 

[Col_Sanders]

I had 3 different motor combos in my Blazer, and all of them took a few seconds to start. New fuel pump, lines, filters, batteries, starter, cap and rotor, and obviously plugs and wires. I didnt change any of those to try to make it start faster, just crap breaking and routine maintenance. Unless it is really taking a while, I think its normal.

 

[Redwookie]

I actually replaced the battery cable from the solinoid and that seems to have done the trick. Strangely it was cranking over slowly but I guess I'd gotten so used to it I didn't notice. Much better now.