rebuilt my motor now it will not stay running. 90 k5

[phrogs]

Ok guys quick background.
Motor gave up the ghost. I yanked it and decided to rebuild it.
Ended up going .30 over on the cylinders. used my original connecting rods on the new pistons did everything else right just like you should.

Rebuild kit from northern auto parts with .30 pistons everything else stock.

This isn't my fist 350 rebuild, Did plenty of TPI corvettes but I double checked everything and it was put together right.

Timing is spot on with the wire disconnected from the ECM I had the timing light on the #1 cylinder wire, and had the timing set right on the Zero on the timing mark.


Since this is my first time really messing with these TBIs I wasn't sure wtf was going on so I parked the truck. I only had a few days to mess with it before I had to come back to work in Afghanistan.
So im sitting here in the dust bowl trying to figure out what could be my issue.


The symptoms

The truck would start and idle but if I put the gas down it would just chugh and die. This is with the brown and white or whatever color ECM wire disconnected.
when I thought it was ruining halfway decent I reconnected the ecm wire to see what it would do.

The timing light shows the #1 spark plug is firing at the twelve oclock position of the dampener this is with the ECM wife connected so the advance is jumping out there.

The battery was disconnected so the ecm was without power for months.
Truck was parked from the time I pulled the engine till rebuild was done. was almost 8 months that it sat.

If I connected to wire back up it wouldn't even idle.

I didn't check the CEL but it was on. (Update there was no CEL)

I'm thinking I have a bad sensor somewhere or perhaps my injectors are gummed up with that ethanol fuel.


Any pointers will be helpful.
And I know without the CEL codes its impossible to know I guess I'm really wondering if I need a new a chip burned because I went .30 over on the pistons.


Thanks
johnny

 

[eagle mark]

Timing should be about 12-16 with bypass wire connected after being set to 0 bypass disconnected.

There's no reason a stock chip won't run 30 over. Your issue is elsewhere.

You say CEL is on so there's your sign! Here's a link to read codes and at least get pointed in a direction:
http://coloradok5.com/forums/showthread.php?t=240425

If there are no codes set and the ECM is happy? The way to know is turn key on and watch light, it should come on, blink and stay on till engine is started then go off.

Couple things these TBI EFI systems can't help with is low fuel pressure? Have to read that with a gauge. And vacuum leaks are killer!

 

[phrogs]

Thanks, I didn't think the bigger pistons would do anything but you never know till you ask some people who know these things.


I'll have to get the codes when I go home and I know it's impossible to trouble shoot without them.


What's a good source to replace the hard vacuums lines under the air cleaner?

I'll also have to plug into fuel pressure gauge and check that.


Thanks.

 

[phrogs]

OK I just got home.

Hooked up the battery and the truck fired up, Stuck at a decent idle.

So I do not have a Check Engine light on. Not sure why I thought I did before but I have no Codes posted.

Engine is running and idleing fine right now. I took it for a road test and it seems to be running ok. Its not really getting up and going like I remember it doing but Im wondering could it be the ****ty ethonal fuel that's in it?

I have about a 1/4 tank of fuel right now and this fuel is pretty old well over a year old. Wonder if I should just go top it off with new fuel or should I try to dump this crap?


Also need to dig out my fuel pressure guage and see what it is running at.

 

[eagle mark]

Dump the fuel! Ethanol or E10 has a shelf life of about three months, less if air is present. It attracts moisture and then separates and the water is on the bottom.

As a test you could disconnect at fuel filter and fill a glass jar. The fuel will look cloudy. Let it sit still for 30 minutes and you'll see the puddle of water on bottom.

If you ever leave vehicle stored long time run it as empty as possible and fill with non ethanol fuel and no issues one year later. This goes for lawn equipment too!

 

[phrogs]

Believe me I would have filled it up with non ethanol fuel but the last time this truck was filled up was on a road trip. No choice but to use that trash fuel.

 

[dyeager535]

I second that. Both my car and truck sat for about a year (can't remember if Dad drove them during that period, so gas was either a year, or six months old) and both had serious problems running due to the bad gas.

Car is OBD2 and would run ok at idle and at part throttle cruise. Anything else I'd get the "serious problem" flashing CEL, which was a cylinder 1 misfire code, and you could feel it.

The truck, being OBD1, just ran like garbage when trying to accelerate.

Car took a couple full tanks to get it running 100% again, truck only took one, but that's ~30 gallons of new gas at once, where the car takes about ~10 gallons at most.

Based on the very first post I would have suspected the in-tank hose to have split, except for the amount of time it was sitting.

FWIW, in 2005 the truck (same motor) sat for an entire year with non-ethanol fuel in it, and I had no problem driving it on that gas. I agree that ethanol "goes bad" far faster than non-ethanol does.

 

[phrogs]

Well I decided to risk it and I drove to get gas the other day. She was running but would not stay idling while in gear I would have to put it in neutral to keep it going.
Topped it off with fresh gas it was down below a 1/4 tank on the gauge. Been driving it and she is actually running pretty well now, even stays idiling when in gear.

 

[phrogs]

Now this bit h doenst want to stay idling after I come to a stop while it is in gear again. More trouble shooting tomorrow. It worked for like one test run the. I took it out Saturday night and had the idiling issue again.

 

[eagle mark]

Pull the fuel filter and try not to spill! Drain it in a glass jar and let sit for 20 minutes and see how much water is in bottom? Water will be in bottom of jar and the rest will be cloudy.

If it were good gas there would be no water in bottom and gas would be clear... well clear gas color not cloudy.

 

[dyeager535]

Just an FYI, the strainer in the tank is supposed to prevent water from getting into the fuel lines. I had to doublecheck my service manual, someone in the past called me a liar when I said that, but it's true.

Not sure how effective it is at that, even if it did work like it was supposed to, completely submerged in water I assume it would have to pull it through.

 

[eagle mark]

It may say that and I'm not calling you a liar, but I assure you I have seen many filters with water in them...

 

[phrogs]

Well the fact is mine is 24 yrs old now most are older they do fail or go bad. But with the ethanol in fuel who knows what's going on.

 

[dyeager535]

Very good point. Ethanol kills everything else apparently, so it certainly could. And I've seen those filters rubbed through, so there is certainly a way for water to get in there.

Here is a question...Heet or whatever it is, says it picks up water. It's alcohol, right? Is it possible ethanol does similar, not to mention attracting more water than fuel used to in the past?

 

[eagle mark]

Well the fact is mine is 24 yrs old now most are older they do fail or go bad. But with the ethanol in fuel who knows what's going on.

I have done a couple pumps in the last year that failed do to the stock black filter on bottom of pump deteriorated and sucked the shreds in the pump.

New filters are differant material and white... and I think ethanol resistent, the old black ones were not...?

Have to find a chemist! IIRC the Heet/Alcohol mixs with water so it can be sucked up and burned? Not frozen in lines?

 

[dyeager535]

Yes, which makes me wonder if that property of the alcohol will allow it through the "sock" filter. Which would explain why you see what you do in the filters.

Hope those white ones are ok with ethanol, that's what I've got in the truck!

 

[eagle mark]

I did see a white one I replaced after three years when we updated the motor and needed a bigger pump and it looked fine. I'm sure everything now a days is compatible with ethanol. Pretty sure nothing was truely compatible back in 87-91?

The black original still looks more like a screen then the newer white ones look more fine, like a filter...

 

[80' 427]

Funny how us regular ethanol runners never have problems. I have trucks with years old gasoline that run fine. I run it in everything except my diesel and truck that is on lpg.

 

[eagle mark]

I've heard the same thing from a guy in Canada. Not sure why, maybe a different ethanol or different process?

In newer vehicles and sealed fuel system it is way less of an issue then older metal tanks, carbs, vented to atmosphere etc...

For example there's a guy on another forum who works in a lawn mower shop and see's the damage to carbs and puddles of water in gas tanks on a regular basis. They have a big sign for everyone to run non ethanol!

The vented tanks are the worst for attracting moisture! I've fixed several neighbors lawn mowers each spring and they are all the same story. E10 fuel and stored all winter. Come spring they don't run? Pull float bowl and you can see a puddle of water and a corrosion line around float bowl.

Now when fall is coming they run non ethanol and store them full and they start right up in spring!

Even before E was introduced into fuel, old fuel was still an issue as it went bad. You've never seen or smelt old stale gas?

Aviation fuel is the only one I know of with sealed stored shelf life of many many years!

 

[phrogs]

Funny how us regular ethanol runners never have problems. I have trucks with years old gasoline that run fine. I run it in everything except my diesel and truck that is on lpg.

Perhaps the funny part is that we haven't been running it for ever, yet now that we are it causing us issues.