'88 RR 3.5 EFI - need to upgrade EFI system

**hiker** · 15th October 2008, 04:44 PM

Hi all

My 88 3.5 EFI has decided to be stubborn .... running like a new one for several months and then decided to have a fuel starvation issue. NRMA roadside expert squited some 'Start Ya Bustud' in the plenum chamber and it started straight off. He then proclaimed 'fuel problem, probably faulty fuel pump or filter - I'll organise a tow truck'

Here's what I've done over the past few days

1. Replaced the fuel filter
2. Checked that the pump is pumping to engine bay (squirted fuel into bucket)
3. Swapped ECU for known good one
4. Swapped relays under front seat with known good ones
5. Unplugged and jiggled all visible connectors and sprayed with CRC connector spray
6. Swapped air flow sensor unit with known good one
7. Checked spark plugs - sparking OK

My assessment is that a component is failing to instruct the injectors to inject - there is fuel and there is spark

If there's a fix which is a reasonable long term investment, then I'd be happy to look at it - maybe a replacement EFI system? or maybe reverting to carbs, or putting it into the line up for LPG conversion (about 3 months delay)

any input appreciated

thanks

mike 90 RR · 15th October 2008, 05:04 PM

Hi Hiker
Frustrating ain't it

Check out this thread that I started in April

I started with a car that was just getting harder to start each day and played up all the time .....

Basically .... make sure you have no voltage drop issues ... then move on from there

A "hint" of voltage problems would be a "dim glowing" alternator light (that you can see when night driving) that grows stronger as you turn on more lights

Hope it helps

Mike

mike 90 RR · 15th October 2008, 05:17 PM

Try this one .... 6th line down

http://www.aulro.com/afvb/range-rove...nic-dizzy.html

**hiker** · 18th October 2008, 05:24 PM

thanks Mike

Had all the straps redone last time - now have replaced ECU, AFM and all hi tension leads

Cold start injector now operates - squirts just enough fuel in to start engine for about 4-5 seconds, then dies again

Is it possible that 1 bad injector kills the other 7?

cheers
hiker

**POD** · 18th October 2008, 08:06 PM

My understanding is that in Australian conditions the cold-start injector will virtually never operate- it is only required in extreme cold.

mike 90 RR · 18th October 2008, 08:26 PM

Originally Posted by hiker

thanks Mike

Had all the straps redone last time - now have replaced ECU, AFM and all hi tension leads

Cold start injector now operates - squirts just enough fuel in to start engine for about 4-5 seconds, then dies again

Is it possible that 1 bad injector kills the other 7?

cheers
hiker

Can you do a direct voltage supply to the fuel pump // Just to make sure you have no faults .... as it all sounds like a weak fuel pump or a voltage problem to fuel pump

If one injector doesn't work properly .... it would just run on "7 legs"

Mike

**BigJon** · 18th October 2008, 10:35 PM

At the rear of the intake manifold there is a vacuum switch which turns off the injectors on "over run". This is purely an emmission control / economy switch. I have been told this can fail, which will stop the injectors from working.

Look for an electrical switch with vacuum lines going to it. Disconnect the electricals and bridge them. There is a fair chance that this is your problem, the guys at TRS in SA told me about it. I have bypassed mine as above. The only drawback is possible higher fuel consumption (which I haven't noticed, but I do very little around town driving).

lokka · 18th October 2008, 10:38 PM

Originally Posted by mike 90 RR

Can you do a direct voltage supply to the fuel pump // Just to make sure you have no faults .... as it all sounds like a weak fuel pump or a voltage problem to fuel pump

If one injector doesn't work properly .... it would just run on "7 legs"

Mike

Could also be a dodgy fuel pressure reg the one that lets the left over fuel in the rail return to the tank cause if there is'ent enough pressure in the injector rail they wont fire enough to get it going

mike 90 RR · 19th October 2008, 11:15 PM

Originally Posted by BigJon

At the rear of the intake manifold there is a vacuum switch which turns off the injectors on "over run". This is purely an emmission control / economy switch. I have been told this can fail, which will stop the injectors from working.

Look for an electrical switch with vacuum lines going to it. Disconnect the electricals and bridge them. There is a fair chance that this is your problem, the guys at TRS in SA told me about it. I have bypassed mine as above. The only drawback is possible higher fuel consumption (which I haven't noticed, but I do very little around town driving).

Originally Posted by lokka

Could also be a dodgy fuel pressure reg the one that lets the left over fuel in the rail return to the tank cause if there is'ent enough pressure in the injector rail they wont fire enough to get it going

... I learn something new every day ....

.....

**PhilipA** · 20th October 2008, 02:19 PM

Hiker, what behaviour caused you to call the NRMA???
Were you just driving along and it cut out? if not please describe the situation and what the car does.

One of the few mechanical parts of an EFI system is the TPS ( throttle Position Sensor). they are like the volume control on an old radio, and as they wear they can get gaps in the resistor. The computer then doiesn't know what the heck to do.
If it just cut out , that may be your problem.
Regards Philip A

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