kenny estoven

I have swapped the CVH in my 1990 mk 4 xr3i for a 1600 silvertop zetec. I have used the original fuel injection set up as on the last of the mk4's but with an adaptor plate between inlet manifold and cylinder head and a spacer in the inlet to raise throttle body above the cylinder head cover.It uses a coil pack and individual injectors like the zetec does. The problem I am getting is that when I start the engine it starts no problem and revs straight up to maximum without applying any throttle. The obvious thought to me is that it must have a huge air leak but I have checked and cannot see one. Does any one have any ideas what could be causing it however obvious as some times you try to look to deep into something and miss the obvious.

Regards K

Versus_Creations

iTrader: (1)

Have you unplugged the idle valve.

gup

iTrader: (1)

Check the top part of the inlet where the throttle cable bracket goes I've seen there not sitting correctly and hold the front part of the inlet up even when it looks and tightens up fine

kenny estoven

Versus_Creations, I have tried it with idle valve unplugged and plugged in and is still the same. I have also tried unplugging TPS which also had no effect.
gup, I have had the throttle housing off to try a later one to see if I could avoid using a spacer plate between the 2 halves of the inlet manifold so will check this as this could provide the amount of air needed to demand enough fuel to run at max. I am also going to check the MAP sensor, its connections and pipework as if this is not working the ecu will use throttle position sensor to determine the amount of fuel being put in by injectors by providing a value. which could be idle, part load or full load.

Thanks for your replies, I will let you know how I get on.

K

gup

iTrader: (1)

Are you using the right gaskets between the spacer plates on the head
Have you looped over the two little inlet ports on the bottom part of the inlet by the injectors

kenny estoven

Yes all new gaskets fitted, I was supplied the wrong ones twice, and adaptor plate between head and inlet manifold fitted correctly as I built it up out of car. I will double check everything just to satisfy myself.

Thanks.

K

haz87

Simple question, but you have checked the throttle cable isn't jamming the butterfly open or anything simple like that.

kenny estoven

Butterfly not being held open. I have taken injection system off and refitted it again making sure everything is seated correctly and tight. It now runs at 3500 rpm so I am thinking the ECU ghas lost its settings and needs to receate them. I am going to plumb radiator in and run iyt up to temperature and see what happens.

K

kenny estoven

removed injection system and refitted, revs came down to 2500- 3000 so going right way. Plumbed in radiator and ran up to temp no change. Sprayed injection cleaner around manifolld area and there was a change in revs, obviiously an air leak some where. Took injection system off again and strpped down rebuilt with more new gaskets and hylomar still reving at 2k. sprayed again with injection cleaner, revs rise when sprayed near adapter plate to head. Stripped down again, on checking adapter plate manifold stud stick out of back by 2-3 mm, so gound flat to plate, coated gasket and plate with hylomar and rebuilt again , started up, now runs at about 1000rpm on tick over, result !!! just has a slight misfire on tick over but revs clean when throttle opened. Time to rebuild front suspension and get it on floor to see if it is any better under load.