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Tii Doesnt Like Heat


MarkC

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Searched in advance but didn't find anything.

Stock '74Tii with Crane XR700 Electronic Ignition being the only change, blue coil.

Saturday: Rough starting for a group drive, idle while everyone gets going, temp approx. in middle. Drive 3-5 blocks to gas station & shut off (I didn't get gas). Fire up, temp 1/2 way between middle line & red, seems fine, drive 2 miles to highway in stop and go, temp continues rising but not in red. Enter high and car starts sputtering/missing/backfiring (S/M/B). Return home and hop in more modern car to lead the drive. Don't attempt to drive again until today.

Monday: Car fires right up, take same route to highway except without the stop at the gas station, temp 1/2 between middle and red entering highway, smooth running for 25-30 miles, get home fine. Let car idle until nearing red in driveway, try to drive around the neighborhood and S/M/B again, drive a few blocks and return home and shut off in garage. Visually inspect engine and check electrical connections, nothing blatantly out of the ordinary.

Fire it up 10 minutes later, running better, but still S/M/B around the neighborhood, just not as bad. Continue driving and eventually it returns back to normal smooth running and I hop on highway for a couple exits and return home with no issues.

Anybody have any thoughts on the cause or what to look for when this is happening? Unfortunately when this happens I manage to get the car home under it's own power and hop in another vehicle since I'm usually trying to get somewhere. I also thought it to be an electrical gremlin (might still be), but since I didn't change a thing and it returned to normal driving I'm not sure.

TIA.

Mark C.

'74 Tii Atlantik

'74 Golf (RIP)

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yer electric fuel pump is turning to krap - old age

is it noisy?

fuel system pressure test - under the same driving conditions and

when it starts to sputter again - pop the hood and look at the gauge

(hint - 30psi is the right finding)

last fuel filter replacement ?

remove the filter and empty contents

into a jar -blow into the OUTLET so the filter empties

out the INLET side INTO THE JAR - REPORT FINDINGS

you own a fuel injected car - time to buy a fuel pressure test gauge

'86 R65 650cc #6128390 22,000m
'64 R27 250cc #383851 18,000m
'11 FORD Transit #T058971 28,000m "Truckette"
'13 500 ABARTH #DT600282 6,666m "TAZIO"

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yer electric fuel pump is turning to krap - old age

is it noisy? No, not really, same as when I acquired the car...I do have a spare though.

fuel system pressure test - under the same driving conditions and

when it starts to sputter again - pop the hood and look at the gauge

(hint - 30psi is the right finding)

last fuel filter replacement ? Less than 1000 miles

remove the filter and empty contents

into a jar -blow into the OUTLET so the filter empties

out the INLET side INTO THE JAR - REPORT FINDINGS Will do

you own a fuel injected car - time to buy a fuel pressure test gauge .

Will report findings.[/b]

Mark C.

'74 Tii Atlantik

'74 Golf (RIP)

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if it is the fuel pump, my personal one-time experience has been to replace it with a 5-series pump as documented by Keith Kreeger.

http://www.my2002tii.com/tii-fuel-pump_how-to.htm

I had the fuel pump blues and just this past January finally did the Kreeger method. I had tried a rebuilt (available from Mesa Performance) but it didn't work, literally. I had a spare but it began faltering within 8 months.

I finally decided that if I could get 30 trouble-free years from a new 5-series pump, well, I shouldn't be driving 30 years from now anyway. (I got 35 trouble-free years from the original pump).

Cheers,

Carl

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yer electric fuel pump is turning to krap - old age

is it noisy? No, not really, same as when I acquired the car...I do have a spare though. The replacement pump was more quiet than the previous pump.

fuel system pressure test - under the same driving conditions and

when it starts to sputter again - pop the hood and look at the gauge

(hint - 30psi is the right finding)

Fuel pressure came in between 22-25 psi with BOTH pumps, not sure if this was the pressure test install or the gauge not being the most accurate, short of dropping more than $20 on one at Harbor Freight. The new pump didn't hop around as much as the previous pump on the gauge.

last fuel filter replacement ? Less than 1000 miles

remove the filter and empty contents

into a jar -blow into the OUTLET so the filter empties

out the INLET side INTO THE JAR - REPORT FINDINGS

Fuel blown out of filter did not have any sediment in it, it's now lawn mower fuel, as I expected it to be

you own a fuel injected car - time to buy a fuel pressure test gauge . Purchased one at Harbor Freight, not sure how accurate it is, both pumps yielded similar PSI, although the new pump was slightly higher and did not bounce around as much on the gauge.

I could not replicate conditions (high engine temps) that caused sputtering/missing/backfiring because a storm rolled through and crushed the temperatures. Will try to replicate the failure conditions tomorrow evening to see if the pump solved my issues.

More later.

Mark C.

'74 Tii Atlantik

'74 Golf (RIP)

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Sidenote: I had some knowledgeable mechanics over this evening, fired it up, drove fine, came home, let temps rise, and the sputtering & missfiring started up on que before starting any diagnosis.

Tomorrow I hope to have warm enough temperatures after work to replicate the failing point to test if the fuel pump was the culprit...less I chance my 3rd AAA call of the year and just go for it and drive to work.

Mark C.

'74 Tii Atlantik

'74 Golf (RIP)

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some good info: http://www.my2002tii.com/june_2001.htm

could be fuel starvation ?? I had this happen on my 1948 Chevy truck. I discovered that the pick-up tube inside the gas tank was packed with rust particles. When the engine was not running, the fuel would gradually seep throughout the particle clog and fill the tube. When the engine was started this fuel would get pulled out and the truck would run fine for a few minutes. Eventually the clog effect would take over and not let much fuel through, thus starving the engine.

So, maybe there is "some blockage" "somewhere" in the fuel system from tank intake all the way to the fuel injection pump, and back to the fuel tank.

Wild Idea 1: there is a small in-line filter on the outlet side of the fuel injection pump which goes back to to fuel tank. Perhaps it is clogged and no fuel will push through, thus back-pressuring so no fuel can get to the injection pump, etc.

Wild Idea 2: have you removed from the gas tank the sending unit/fuel intake assembly. At the bottom of that is a fine-mesh filter.

Cheers,

Carl

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Thanks Carl. Last summer/fall we did some troubleshooting on the things you mention. I'm pretty confident my fuel system is free flowing based on last night and troubleshooting last year. The car has been driven sporadically, but nothing significant other than a romp to Cincinnati for Eurotrash's spring run.

some good info: http://www.my2002tii.com/june_2001.htm

could be fuel starvation ?? I had this happen on my 1948 Chevy truck. I discovered that the pick-up tube inside the gas tank was packed with rust particles. When the engine was not running, the fuel would gradually seep throughout the particle clog and fill the tube. When the engine was started this fuel would get pulled out and the truck would run fine for a few minutes. Eventually the clog effect would take over and not let much fuel through, thus starving the engine.

So, maybe there is "some blockage" "somewhere" in the fuel system from tank intake all the way to the fuel injection pump, and back to the fuel tank.

Wild Idea 1: there is a small in-line filter on the outlet side of the fuel injection pump which goes back to to fuel tank. Perhaps it is clogged and no fuel will push through, thus back-pressuring so no fuel can get to the injection pump, etc. That's a possibility I can check it if I get another failure with the new pump installed. Semi-fuel related: When I first acquired the car, there was no vapor canister under the rear deck, when I filled the tank all the way up, sloshing gas would get siphoned all the way through the car with the vacuum on that and flood/choke out the engine.

Wild Idea 2: have you removed from the gas tank the sending unit/fuel intake assembly. At the bottom of that is a fine-mesh filter. Yes, this was done after my epic Vintage failure toward the end of last summer, tank was spotless visually with no sediment and the screen was intact. Also, given everything we found last night, I'm pretty confident it's not a fuel supply/return issue. Hopefully the new pump is the ticket.

Cheers,

Carl

Thanks again, after I can replicate the point I know it will fail I'll report back. Also going to start logging some miles on it until I need to contact AAA for another tow (knock on wood).

Mark C.

'74 Tii Atlantik

'74 Golf (RIP)

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  • 3 weeks later...

I just had another wild idea, again from my 6-cylinder Chevy truck. 4 of the 6 spark plugs had insulators with tiny cracks. I don't know how that happened, but it did. I just happened to have the engine running after dark and opened the hood to check something else and saw the major lightning storm !!

Cheers,

Carl

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