78 bus ,super fast idle problem

kps73 · Post by **kps73** » Tue Nov 13, 2001 2:52 pm

I purchased a 78 westy with the stock 2.0,f.i. engine.It has been sitting for 2 years.I tuned it up,cleaned the gas tank,changed the fuel filter and all lines, it started up no problem.The problem is that once it warms up the idle goes real high and only comes down if I turn it off and re start it.It then goes real high again if I give it any gas.I replaced the exhaust$$$,and egr charcol thing but the egr light stays on.I know I need to get a multi meter to check the sensors but was wondering if anyone can give me any hints on this problem.I wish to keep the f.i. and do not want to install carbs.Can someone allso tell me where I can find the trouble shooting info for the sensors etc.Thanks for any help in advance!Ken

germansupplyscott · Post by **germansupplyscott** » Tue Nov 13, 2001 3:49 pm

first off, yes, keep the f.i. it is not difficult to maintain and has an unjustified bad rep. twin carbs are very good, but expensive. you CAN fix the fi system with simple tools and a good multimeter.

start with some simple things - high idle should be caused by too much air in the intakes at idle (it could be more complicated, but look at the simple things first) - where is the air getting in? a likely place is from the throttle valve not closing completely, or the mixture screw too far out. throttle cable may be adjusted too tight or binding. push the throttle home against its stop with the engine idleing high. any lowering of idle? try disconnecting the accelerator cable with the motor running. lower idle?

above all, be methodical. look for all the mechanical faults first - cables, fasteners etc.

next check all the hoses and air passages.

then make sure all electrical connections are sound - there are lots of them and they are almost always suspect in an old van, especially one that has sat for a while.

here are some references:

haynes manual is good, has a decent supplement on fi system.

type2.com library has lots of excellent stuff on fi. poke around there and you'll be glad you did. there are several great links with step by step procedures for troubleshooting the fi system. look for the bosch manuals link and get them, print them and you will be set.

this forum is very good.

good luck,

scott lyons

Bob Ingman · Post by **Bob Ingman** » Tue Nov 13, 2001 5:55 pm

And if all else fails contact Ray Greenwood. He knows them well. Good Luck. Bob

Corvair Guy · Post by **Corvair Guy** » Wed Nov 14, 2001 8:36 am

Here is a good site for diagnosing your fuel injection system

http://members.home.net/sdakhlia/bus-stuff/

Good Luck

ray greenwood · Post by **ray greenwood** » Wed Nov 14, 2001 9:04 am

If it starts and runs at correct idle when cold...and then speeds up....punkinfair is correct. Air is still entering. If it has been sitting still for a while, the Aux. air regulator not closing will be immediatly suspect because of corrosion. Other things besides obvious vacume hoses. Intake boots, throttle body seal, runner to head gaskets, injector seals, the little boot between the aux air regulator and the center intake plenum, the cork gasket at the oil tower where PCV hooks in...and if you have D-type injection (which you should not) the diaphram in the MPS. It's best to just replace everything rubber in this situation. Oil and age will kill all of it. Ray

germansupplyscott · Post by **germansupplyscott** » Wed Nov 14, 2001 9:34 am

one other thing:

i don't have egr on my bus, so i can't be positive, but i THINK the egr light is triggered by the speedo cable and there should be a trigger box in the front of the van under the kick plate somehwere (drivers side). this will be a black box with the speedo cable entering it on one side and exiting it on the other. it should have a reset switch. i don't thing the egr itself has any sort of electronics connecting it to the dash light.

ray greenwood · Post by **ray greenwood** » Wed Nov 14, 2001 4:43 pm

Yeah...usually the egr lights come on in those days because of milage trigger in the speedo. Ray

kps73 · Post by **kps73** » Wed Nov 14, 2001 7:30 pm

Thanks all,I will replace all rubber!I will use the vw type[cloth wraped]Thanks for the egr tip ,you where write on about the light being triggered by the speedos hidden black box.Thanks to all,I will keep you posted.ken

77camper · Post by **77camper** » Tue Nov 20, 2001 10:08 am

Did you try adjusting the idle speed yet?
There is an adjustment screw at the base of the inlet. It's possible it could have backed out from vibration. As far as any air leaks, my van wouldn't run at all when it had a leak on the inlet duct.
If you need any more info you can email me at
[email protected]
Good luck

[This message has been edited by 77camper (edited 11-20-2001).]