Runs Great, until it warms up....? Options

[rmital]

All new fuel injectors, seals, fuel lines. ('73 1.7L) The car runs great...for the first 10 or 15 minutes. Then it starts to sputter, or lose power. Reallly jerks around, then kicks back in, then out again....pull over and idols slow and erratic.

I'll let it sit for a while, runs great again then same problem.

Any advice.

Thanks,
Ray

[sk8kat1]

if I am not mistaken -- until warm the cold start valve kicks in to make it run a bit rich .. I would say it sounds like you are not getting enough fuel so it gurgles and sputters and wants to die after it warms up ...

I would think injectors , fuel filter , fuel pump ...... maybe even the pick up in the tank itself could have picked up some crap and not pulling the fuel well

could be lots of things .. probvly want o start w/ the cheap first .. fuel filter and such

[brant]

how was it runnig before the tune up?

what have you done to it lately?

usually these problems are related to the most recent things that have been done to the car.

In your case, I'm going out on a limb here and guessing you recently replaced a bunch of fuel lines?

am I correct?

(I've got 2 fuel line Ideas if I'm guessing correctly... )

brant

[rmital]

wasn't running at all...bought the car as a roller.

work done/replace:
ignition parts
air/fuel filters
aar
fuel injectors
fuel injector seals
ingnition condenser
ingnition wire set
most if not all fuel lines

[brant]

Raymond,

I've got three shots in the dark to check first.. if this doesn't do it I'd get methodical and check everything warm (spark, fuel, air, all f.i. values)


I get 3 guesses right?

#1) I'm wondering if you replaced the little 2 inch fuel line between the fuel rail and the fuel injector? Instead of making those 2 inches, cut them back to about 1.25inches. When the car warms up the hoses get warm and more pliable. Then the weight of the rail causes the hose to bend and kink the fuel supply. chokes out the amount of fuel getting to the injector and serious loss of power.

#2) the fuel line under the gas tank. Did you have the gas tank out? Its a common mistake to leave extra length in the fuel line under there, especially if you relocated the fuel pump up front. seems like a good idea, but there isn't a lot of room under there. the extra fuel line gets kinked and the car will run well with the volume of fuel that trickles through for a while, but then the supply can't keep up with the demand.

#3) distributor, and injector points. Is your distributor a matching number distributor for your system. see if you can borrow one from somebody and warm your car up until its not working and then plug in the borrowed distributor. I once had an advance issue that really only became apparent after the car warmed up and no matter how many times I rebuilt the distributor the only solution was to replace it.

those are my top 3
let us know what the outcome is.
brant

[rmital]

Thanks Brant...I'll let you know how it works out.

I'm guessing #1 or #3....leaning toward #3.

[Bruce Allert]

Sure sounds like the CHT to me.
Check the resistance cold then let it warm up & check it again.
Resistance numbers Sensor Temp = 39 deg. F
(ice bath with thermometer) Temp = 61 deg. F
(room temperature)
Temp = 210 deg F
(boiling water at 1000 feet altitude)
0 280 130 003 6.10 K ohms 2.94 K ohms 199.3 ohms
0 280 130 012 NA 2.85 K ohms 191.2 ohms
0 280 130 017 3.63 K ohms 1.74 K ohms 124.7 ohms
Here's the right site
The Right Site

Scroll down... way down & there are other numbers for the CHT.
good luck..... b

[brant]

dang Bruce...
thats a good one..
I was thinking that it might be getting lean, but your right... it could be getting rich instead.

brant

[Bruce Allert]

That site I gave didn't work so I found the numbers from Brads site.
I had nuermous probs. with the CHT until I found a good one.
The Brad Anders Site
.......b

[rmital]

QUOTE (Bruce Allert @ Feb 26 2006, 09:04 AM)

Sure sounds like the CHT to me.

CHT?

ACRONYM for....

[rmital]

got it....Cylinder Head Temperature Sensor.

[Bruce Allert]

QUOTE (brant @ Feb 26 2006, 10:06 AM)

dang Bruce... thats a good one.. I was thinking that it might be getting lean, but your right... it could be getting rich instead. brant

Actually your first thought was right. When it's cold it would run rich. When the CHT warms I'm pretty sure it sends the message to the ECU (electronic control unit) and leans the fuel distribution.

.....b

[brant]

QUOTE (Bruce Allert @ Feb 26 2006, 12:14 PM)

QUOTE (brant @ Feb 26 2006, 10:06 AM) dang Bruce... thats a good one.. I was thinking that it might be getting lean, but your right... it could be getting rich instead. brant Actually your first thought was right. When it's cold it would run rich. When the CHT warms I'm pretty sure it sends the message to the ECU (electronic control unit) and leans the fuel distribution. .....b

the way I was interpreting it...
somewhere on Brad's site he mentions a CHT that is "stuck" with a certain value...

so the thought crossed my head that perhaps his CHT is stuck in a cold value setting... mixture is close when cold, but fails to lean out..

could be either way.

time to get the ohm meter out and do some heavy duty visual inspection of the fuel lines.

brant