My fuel injection will most likely come off my daily driver in the next few months. I hate to switch to carbs, but I'm so tired of fiddling with the FI and not getting any results.

Right now, my biggest problem is that my car won't idle when it's hot. It runs great when it's cold. But once it's reached operating temp it won't idle. I'm thinking that it's not firing on all cylinders once it gets warm. Today I had a lot of errands to run and so at first it was the usual heel-toe at a stop light to keep the rpms up. By the time I was heading home I had to rev to 3000 rpms to get going at all.

It's just ridiculous to have all these 30 year old FI parts, none of which cam be trusted to be working correctly. I have brand new TPS, Head Sensor (NAPA brand), and my MPS was tested and okayed by Jeff B. I checked my Trigger Points on the oscilloscope and they're firing as normal. I adjusted my valves this morning and they were good enough before I changed anything, and now they're even closer.

If I could fix the FI without spending $1000 on parts I would do it, but I don't think that's realistic. Grrrr, I'm just fed up

First of all, make sure the timing is set right-to 27degrees before top dead center at 3500rpms. I think your timing is off.
Get the right CHT
After you do these, then set the idle mix hot either with a CO meter or by ear. The idle must be set when the engine is hot or rather operating temp.
Otherwise, you will be chasing the idle setting forever. When cold the idle is high (1500-1800) rpms by the AAR valve. When the engine is warming up it can hunt alittle bit. When it is hot, the idle should be steady at 900-1000 rpms.
IF you adjust it when its cold or warm you have problems usually because you set it too rich. When the engine is hot it "bogs" at idle from the over rich mixture.
These are the 3 things I see with idle problems beside vacuum leaks.
1. Mis timed
2. Wrong Parts- CHT or vacuum hoses hooked up wrong
3. Set when cold to warm engine temp so

Best I can recommend now
Geoff

The other thing to check for is vacuum leaks. New hoses are easy to do.

Where can one buy a CO meter? I have a 1999 JC Whitney catalog that lists a couple of them but I can't find any on their web site now.

Dude, Napa CHT? get the right one

I am having exact same problem. Car is near perfect in all conditions, pulls smooth to red line, but will not idle hot--heel and toe at every stop. It is an early car ('71) and there is no mixture adjustment on the ECU. I have a VW/Bosch type three FI troubleshooting booklet. It says valve adjustment can cause hot idle problem. Now my bubble is burst because I was hoping that was going to be the answer.

Damn, I'd say the same thing about carbs. I'm just sick and tired of endlessly fiddling with carbs to get them to run right. Of course, with carbs, your engine will idle fine when it's hot. It won't idle when cold.

Jim, that is true that valves out of adjustment can cause idle problems.

That is why everyone says before you tackle Djet issues hit the basics first.
1. Tune up- points,plugs,cap, rotor, check plug wires
2. Adjust valves to spec- too tight or too loose can cause problems
3. Set the timing to 27 degrees BTDC @ 3500rpms, hoses off and plugged on the distributor.
4. Check to make sure ALL vacuum hoses are not leaking
Then adjust the idle hot.
Djet is great when you have ALL the correct parts and it set up, it just runs great.
A MPS that someone has adjusted will do this too.

Dual carbs can be a real headache too, god the cold idle problems is enough to drive anyone crazy.

Jim, I do have a good 73 1.7/2.0L ECU sitting in a box if you want it.

Geoff

Geoff, I have done everything on your list EXCEPT valves. That's next. I checked MPS using ohm meter at ECU plug using B. Anders specs. He says 90 and 350 ohms for the two tests. I get 65 and 225. Is that too far off? I am thinking that the car runs so well except for hot idle that the MPS is ok. Should mention that idle air screw makes no difference at all.

Jeff has my MPS & harness looking them over. I am getting ready to go from carbs to FI.

I don't have any problems w/ cold starting. Don't have any drivability problems w/ carbs at all. Maybe I am just lucky, running DRLA 40's.

I read a thread like this and it makes me wonder if I should just keep the carbs.

Be aware You will get horrible mileage w/ carbs. I am getting 16 mpg around town. You will also have a hard time passing emmisions. My car puts out over 300 ppm in hydrocarbons. When you come inside after working on it you smell like you have been standing around a diesel fuel campfire.

Mark, be sure to read this http://www.914world.com/bbs2/index.php?act...&f=2&t=2347&hl= thread too.

Thanks Jeff.

Just seems like you see a lot of posts about FI problems.

I don't mean to be a dick but I seen/heard just too many stock FI horror stories. Plus you can't hop the engine up. Oh, maybe 5-15 hp, big frickin' deal!

Let's face it I have a beetle with a T1 1600 engine, that I've hopped up to a totally reliable 2 liters and it will smoke any 2.0 D-jet. (were talking engine power here, not handling)

BUT, I'm also sick of carbs and dizzys, they suck.
I mean they can do the job, but there is always something just not quite right with them.

This is why I'm stepping up to the plate and going with a PEFI system with programable ignition!
At least it's modern, and it didn't cost all that much more then a new MPS.

So lets change that impression.

I have two 74 2.0 914s...both have stock D-Jet. Both cars have run superbly since the day I acquired them and I have done very little to maintain them.

My white car has a new FI harness with gold terminals and teflon wire....

My Bumblebee has everything original...red vacuum hoses even...runs perfectly.

These are not monster road machines...but they do funtion well and reliably.

Just a thought. In tuning my Megasquit PEFI I gained a healthy respect for the people who put the D-jet together. First, for most people it has run well for almost 30 years. Second, it adresses some diffcult tuning issues and handles them quite well (large injectors, rich mixture to aid cooling). These were difficult for me. In the end, I ended up with a fueling program that replicates a D-jet.
It was a lot of work to end up with a new D-jet.

On the other hand, I now have something that is new, so it should be more reliable but only time will tell and, I can make changes in the fuel program to accomodate engine changes withe relative ease.

As hard as it is to figure out, the d-jet works well and I would advise people to stay with it unless they have specific reasons to change (D-jet absolutely shot, lots of engine mods, a born tinkerer).

Dave

Jim, if the air bleed does nothing to adjust the idle somewhere you have a vacuum leak or the timing is off. My guess is a combination of vacuum leak, too rich a mix, and the valves need adjusting. Is the MPS is factory sealed?? Does it hold a 15hg vacuum for 5 minutes?

OK, Djet on 914's. Why do people have soo many problems.
1. These cars are 30 years old and have usually had a mechanic along the line "plug and play" with the FI parts so they are not MATCHED. The matching of the parts is important, check Brad Anders site for the proper set of parts for your car.
2. Usually as a engine ages it doesn't have as good a vacuum signature for the MPS, there is not adjustment for this other than to adjust the MPS which most have been. They usually are not even close!
3. Usually they vacuum hoses are old and leaking.
So the bottom line is:
A Djet FI system with mis-matched parts, old vacuum hoses or a high mileage moter is going to have problems! duh! How well will a carb motor run with only 90lbs of compression?
People who have driven my 2056 914 will attest to how well it can run. With 95hp to the rear wheels (about 115hp engine) the car really pulls. But yeah, there is more power buried in it but it is limited by the FI cam. I removed the dual carbs I had on the car and re-installed the Djet. It took me quiet awhile to figure it all out because there wasn't a site like Brad Anders before. After talking to Brad Anders I have learned to tune the Djet using a dyno and testing equipement to really get the most out of the FI.
Chris Reale's car is finally running sweet after finally sourcing good and correct parts plus hooking up the dis-connected injector.





Geoff

I have a single carb on my Subaru. I get 26MPG and no problems at all with it. Cold starts suck, buy hey....

I cannot add anything else to the thread that hasn't been said already. There is a ton of useful info out there now that can walk you through the FI issues. Before you jump ship, go through it a few more times, make sure everything is working, adjusted properly etc.... Once it is sorted out it is a great system

i second that.

my 1.8 D-Jet is running great. all i have done to it so far was replacing 2 injectors right after i bought the car (2 1/2 years ago). well, it was sitting for a year, but it fired right up and is still running fine. need to change the oil and adjust the valves, but that's it.
i'm very happy with the FI ...

Andy

Well we'll see what happens with me. I need to check some things. I'm putting all my hope into swapping the CHT for an old good one I have somewhere (kinda lost it at the moment) and see if that helps things. I was thinking about checking the timing again, and it got me thinking... should we be checking timing hot or cold? My guess is hot. Thanks for all the good ideas.

A couple of ideas that I don't believe that have been mentioned to check.

Have you pulled the plugs to see if it's running rich or lean?

Have you checked your fuel pressure? I had a hot start problem and idle problem because the fuel pressure was too high. Should be around 29-30psi. If you need a gauge go to your local hardware store and ask for a pressure gauge, rig up a t fitting with some galvanized pipe, and some extra fuel line. Also check to see if the pressure holds for about 10 minutes after your turn off the vehicle. If it doesn't hold pressure you may have a leaking cold start injector or fuel injector.

I sn't there an adjustment on the throttle postion sensor for idle? Pelican parts web site has info on that. I think Mike Cooley wrote up something on it.

If you disconnect temp sensor #1 on the intake plenum does it make any difference when the engine is warmed up? When disconneted it should make the engine run slightly richer not sure if you'll notice it. I've got a air fuel ratio guage on my car so I can see it the difference in mixture when I disconnect it.

Hope this helps.

Andy LeVesque

My Ghia got somewhere around 15 mpg with the 912 engine, dual Dellorto DLRA 40's. With the stock 1600 dp, 34 PICT carb, it gets 35 mpg on the highway (with the top up). I don't think that there's anything about carbs or fi that means you can't get good gas milage, but with FI - you aren't forced to trade as much performance for good milage.

huh? is it a stock 2.0 with carbs?
is there that much difference between a 2.0 and a 1.8?
i easily get 30+ MPG out of my 1.8, and i ain't driving it "economical" ...


Andy