another break down

Brant · 06-02-2004, 07:29 AM

Hi everyone,
I think my car might be posessed. Its the 72/1.7FI motor that I have been working on for 2 months.. I finally went through most of the FI and fixed a fuel problem and got everything working well..

It ran good for 1 week, and I installed a crane 700 optical ignition..

New problem: (could be related to new ignition or maybe not) I'd love your input..

Yesterday, started out with a weird idle. It had been rock steady in the past (new vacuum lines everywhere). I would pull up to a stop sign and it would idle down too far like 600rpm then catch itself and idle back up. Pull onto highway with motor warm, at above 4000rpms car starts pulling slowly... down on power.. then engine dies.. After coasting in gear for 2-3 blocks it comes back to life.. Seems to run normal if I don't rev it past 3000rpm.. As soon as it is reved back to 4000 or 4500 it again is down on power, and then dies again. Not bucking, but my guess is that there is no spark.

Once I looked in the mirror when it began running again and saw a big cloud of smoke, which I think was unburnt fuel. So my preliminary guess is that its got fuel, but spark is cutting out.
All fuel lines are new and fuel filter is new also. I can hear pump running. I could have a failed crane ignition, but I wouldn't think that would partially fail instead of good/bad.

Things that have been replaced in the past month include: plug wires, plugs, cap, rotor, fuel lines, vacuum lines, CHT..

how does a coil fail?

brant

Lyle · 06-02-2004, 08:48 AM

Brant, here are two more things for you to look at on your 914.
1) If you take the dist. cap off, then grab the top of the ignition rotor, how far can you move the rotor back and forth? 0.010 to 0.020 inches would be typical of a good dist., but a lot more then that would be a sign of a worn out bushings on the distributor shaft. Normally putting in an optical ignition system would make your engine less sensitive to this problem unless the bushings are so worn out that your optical rotor is bouncing around so much that it is hitting your pickup sensor. My friend just had this problem and ended up replacing the distributor with a new one as a way of replacing the bushings. On his car, you could move the rotor almost 0.15 inches! It still ran but VERY poorly. Seems like extreme measures but we could not find a supplier of just the bushings. Maybe someone who reads these messages would know where to find the bushings and could reply with their own message on where to buy bushings.

2) There are TWO sets of points on your distributor. In addition to the normal set of ignition point that you see under the cap, there is a second set of points farther down which is accessable by removing two screws from the side of the distributor. It is mush easier to check/replace this second set with the dist. out of the car. These points are the trigger points which tigger the opening of the fuel injectors. They need to be replaced about every 50 to 60 thousand miles. A lot of people don't even know about this second set of points. They cost about $50.00 and these points only exist on the D-Jet style of FI, which is what you have on a 72.
Goodluck. Lyle

Brant · 06-02-2004, 09:03 AM

Lyle,

thanks for the tips.. more is always better...
during my previous trial and error running problems in the last 2 months, i pulled the distributor apart twice and relubed/cleaned/checked everything out. The bushings are pretty good, and before yesterday it would pull smoothly/strongly (well strongly for a 1.7) right up to redline...

this is definitely a new problem that wasn't an issue before. I drove the car in the mountains saturday and it ran great.

The FI points looked good the previous 2 times I had the distributor apart and it ran good then too... so I guess they could of somehow gone bad between saturday afternoon and monday morning.. but it was parked so I'm more likely to think water got in there or something else..

still I appreciate the ideas.. and I'll definitely check the FI points again when I pull the distributor tonight.

Does anyone know if coils fail at high rpm or are they just on/off?

brant

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Coils can go "partly bad" and put out a weak spark. That would likely show most at high RPMs and loads.

Most intermittent problems are electrical problems. Try wiggling every wire you can (when you wiggle the coil/spark plug wires, wear gloves for some insulation) and see if that affects how the car runs.

--DD

GPRparts · 06-02-2004, 12:48 PM

Get rid of the optical, get a pertronics. A lot less problems from what i've heard/read/personal experiance. Always keep spare points/condensor in a ziplock in a safe place(in the car) for a rainy night. Good luck, Don.

Brant · 06-02-2004, 03:32 PM

Don,

I've only had this crane installed for 7days now.. so it could be the problem... although the last crane I had ran trouble free in a race car for a dozen years..

I always thought they were dead reliable in the past?

Dave, thanks for your input... (oh.. and small world.. its josh's used but new in the box crane, that I'm sure came from you guys)

brant

philinjax · 06-05-2004, 02:20 PM

The symptom you describe is fuel starvation at power/high rpm, all okey otherwise. Check the little sock fuel strainer in the fuel feed line
fitting which protrudes into the tank. The strainer screen is so fine that it can easily clog up with varnish restricting fuel flow.

You will likely have to pull the fuel tank to check this. One time, I had a skinny armed buddy stick his arm down into the tank (after I had pulled the 8 bolt top cover) and simply pull the screen off the fitting. Worked like a champ, but I don't recommend it.

Phil

elwood-914 · 06-08-2004, 06:48 PM

Brant,
The past couple of weeks I got the smoke treatment once in awhile on startup but only when it was warmed up and only occationally. Yesterday I came home parked and took the truck to town. Now this morning the car would'nt start. This afternoon I got it started but a very erratic idle. If I tried to add gas it would die. I replaced the fireball coil with the ole blue bosch and it fired right up. The crane coil was put in back in December. Hope this helps.

hardflex · 06-09-2004, 04:56 AM

watch your tach. if it's an ignition problem, your tach will bounce all over as it cuts in and out. if it's fuel supply, the tach will remain steady with engine rpm's, even while the engine is dying.

i suspect fuel supply as well.

Brant · 06-09-2004, 06:32 AM

Update.. and thanks to everyone for all of the great tips and ideas...

so I borrowed a few parts from a friend and first replaced the coil with a known good blue coil.... well everyone was right and it didn't seem to be the coil... I drove it around the neighborhood over and over (didn't want to go further away from home than I could walk)...

Car ran great.. and after about 10 minutes the oil temp was coming up and I was pushing it harder... then motor died. Luckily I was able to coast to my driveway and then my wife helped me push it into the drive.

Next, I took the crane xr-700 ignition out and put in my friends known good distributor with points into the car... No other changes.

drove it around for 10 miles until dark with no problems. Waited until the next day (last night) and took it out on the highway for a good 20 miles, again with no problems...

I suppose I still have not ruled out the FI points, but I can't imagine that they work cold and not hot... as a point, it seems like they would either be good or bad all the time...

so I think the crane is the problem. I called crane and they told me to ship it back to them in florida for testing.. No idea what this is going to cost but it literally only has 500 miles on it so I hope its not an outrageous fee.

thanks again everyone.
brant