The car: 75 2.0 d-jet injection.

the symptom:

car was running fine and has for the past 9 months since i put in new FI wiring harness and replaced the coil,wires,plugs,hotspark mod, temp.sensors , mps.
i have been driving it 4-5 days a week thru warm to cold weather and no problem,.
in fact before christmas it was 27 degrees and car started up and ran great, but at some point it would run fine, but if it sat for several days it runs very rough, like ist missing, misfiring or flooded out etc. so thinking it was flooding out due to leaking injectors, i check and tested those 2 were a little , cold start valve is fine.
-first i replaced the CHT , and put new FI points in and at first i thought that helped, it sure ran smooth for a few days - it was on the rich side and when i tested the CHT it was not at spec, i had one that was new and did, so i switched them out, -no problem seemed to improve , was not loading up like before,

in fact 2 weeks ago i even pulled the tank and put in new filters, checked for leaks etc just in case, all was fine. but it had been doing that if i drove it every day anyway- the problem seemed to be only if it sat for several days.

- moving forward, it continues so I order new Bosch injectors- i put those in last night, ran a little rough at first, seemed to clear out quick and ran it out for a half hour. ran great, good power etc. then parked the car and got up this morning go to start it and it barely starts!!!! like its missing or loaded up. - the only thing i can think of is the hotspark module is going? it does not seem to be fuel related- it thought it was -

timing , valves etc has all been set, checked. - after going thru all the FI and fuel i now think its electric, but that is all new within the past year!

I have verified all connections, all leads and wires. FI ground contacts were rechecked making sure of good contact etc.

suggestions ?

Phil, I hate to be the first to post this, but rip all that FI crap off, get a good set of Carbs and drive it. I know I'm a minority here about FI vs. Carbs but you have spent $$$ and lots of time on this and its still not working correctly or reliable. Sorry my .02 cents.

Oh shit! here we go again. Didn't we do this two weeks ago? He's trying to get his djet dialed in. why don't we try to help him that like he asked. Thank you.

Phillip, go read what I postd at the club.

Or check with Zach. I think he has had it with carbs and is re-converting to FI. Is it humid where you live. Parked indoors or out at night. Phil, what is the "Hot spark" module? Does it spit out black exhaust? Or can you smell gas in the exhaust fumes? Have you disabled the cold start valve (5th injector) to see if it is flooding? Is the AAR fully functioning. Does unplugging the TPS have any effect?

Dang, Phil. You are making me nervous about converting my green 914 back to FI!

Hopefully it doesn't come to that. FI is nice.

Hotspark module? How does the spark look at the plugs? (Pull one, ground it to the case, crank, look for big fat blue spark.)

good questions-- AAr fully functioning, the hot spark is same as the petronix - i have an extra, might switch them out to see if that has an effect,
it was pretty sooty exhaust and i knew it had been running pretty rich, so i was trying to get that dialed in, when it got worse, and i have the ecu all the way as lean as it will go,

- might yet be a bad MPS- scott in NH is callibrating and resealing a couple i had for me, when he has them done i can switch them out to try that as well

does seem gassy rich like leaky - that but yesterday i pulled the cold start valve and it did not appear to be leaking at the time but we are warmer now, but at 60 degrees this morning , hm. well i will disable it just in case b- that really was my first thought- it was so bad this morning it really felt like it did when the FI points were not grounding properly, but i rechecked that last night, so now i'm kind of

i might be running rich etc but it feels electrical and i'm missing something- could be simple. -- i 'm going to switch out the cap and rotor tonight--
it almost feels like when my 69 healy had a bad coil but that was only when it got hot,.... so different. .

sorry to start the whole fI vs. carbs. - when it runs its really great - and my last 2 tanks had bee 26- 27 mpg in town here,

. and it ran great last night.-

oh and last spring i put in new runners plenum, throttle body and seals etc. no vac leak, and the
TPS has a new board and was set at that time, it had been bucking but it really went away with the new TPS board.

So.....It clears up once it is warm???

I know, - but they both have their problems- keeping the jets clean , trying not to use non-ethenol gas etc etc- our mid grade non-ethenol gas is at $3.50, reg. is $3.12 they are really gouging. i used to get it for only 10cents more than regular.
but anyway., i had carbs on my 69 healy and always had problems with linkage, and getting them balanced and staying there. - then there is the cold start issue ,

the idea was to keep it original in that sense, and learn the FI, run it and enjoy it, and i really have done that for the past 6 months overall, a small issue here and there with a loose wire, or a bad sensor.

last big issue i thought i would scrap it but it ended up just being bad FI ground and wiring, so i'm hoping its just a bad connection , wire, sensor , coil or something i have not eliminated-- someone said i could have an issue in the ECU too, but that is the most unlikely and i wont go there until the last resort.

but.... if you see a lot of almost new FI stuff in classifieds..... you know i gave up...

yep, it did,- well i did not have the time or the patience today, but last night it did clear up eventually and ran out great drove about 15 miles came home parked it in the garage, and i had just replaced the injectors too. could the Hot-spark module do that if it was going bad? ---
i need to pull the plugs tonight a take a closer look - did not do that last night, but i almost was getting the idea that it acted flooded out , but again ive seen similar reaction to bad FI points or grounds- and those i checked, just replaced the FI points plate too and it ran good for several days after i did that. - that was last week - it ran fine last week drove 4 days in a row, , , then the car sat for 5 days and its back to same thing.

pw

I believe that electronics, for the most part, will goof up more when warm. Check the spark at the plug when warm vs. cold. Break the hose loose at the AAR to be sure it is sucking air when cold. Verify ohm readings at CHT sender. Will cold idle improve if you ground the CHT or disconnect the TPS (I know that you said it is new but...) Check your fp. It shouldn't change but worth double checking. BTW, I've got the same set up as you on one of my 914's.

Check the electrical connection at the CHT. If it is opening when cold, it will go max rich until it get connection, then settle down. Check the connector on the wire that goes to the ECU. Is it good and tight, all strands still hooked up?
Tom

Drove to work the last few days- what I found was the plugs were really sooty, pretty fouled up from running too rich. I double checked the cht, I think the connection was not tight, and the tps was
off, so it was a little low on idle at start up, whereas now it fires up and idle is a good 1600 cold, but a good 900 when fully warm. Cleaned the plugs, leaned the idle. I still think the mps is off causing the rich running but what I did do helped. I don't think it is the ecu .
O will know more when I can run it with a different mps and compare. And o will have the o2sensor in next week and will be able to hook up my a/f meter and I will know exactly where I am.

I had a CHT (Cylinder Head Temp.) die on me while driving.
(I think its very rare for this to happen)

Lucky for me, I was broke down the street from a VW repair shop.
The guy there guessed a CHT. had a spare, I trade them out.
Drove home.

Ill admit I simply don't remember how much PIA they can be.
but got it done.

Made a better tool (welded a long cheap socket to a rod, cut a slot for the wire)
Change out the good spare and put a new one in.
(Really wanted to try the tool)

If you have done all the requisite checks on the fundementals......my vote would be a partially broken diaphram on the MPS or the ecu...