Chevy & GMC Vans

I would also test the MAP and TPS while I was at it.

without an EGR, try resetting the timing to about 3 or 4 degrees btdc.
See if that helps.

I only get code 12
I am going to drive it to work and check it again

Try advancing the timing a couple of degrees, you may be surprised.
I had a MAP issue once too where it def did not like me giving it the gas pedal.
Turned out the MAP plug had simply come loose, in my case, and I just plugged it back in.

Today's up date
Drive to work was very slow and lumpy under load
Still no codes
Changed the temp sendercthe one next to the thermostat ( no change)
Put it on a 4 gas analyser and noticed the lambda reading was high .
Disconnected the lambda no change on the readings .
Managed to cross reference the part number on rock auto to a common Renault part sold in the UK so I ordered a new lambda and fitted it
Lambda readings now in spec at idle and change throughout the rev range .
Road test and still sluggish but better
Advanced the timing ( not sure how much I just drove until I found the happy spot)
It's now running the best it has its still sluggish under load and under full throttle it will hesitate and have a slight miss.
I am going to change the injectors and service the tbi unit and try again ( I should have the parts by Tuesday )
I am in new York the first week in November on holiday so I am going to buy every possible sensor I can while I can save on the shipping to the UK
I will solve it its just a matter of time and money

Have you done a compression test?

No compression test .
It ticks over fine you could could put a glass of water on the air cleaner and it would hardly ripple . It's not over heating or using any water or oil .
I think I bought someone's problem that they gave up on

captaincon wrote:Thanks for the replys its a tbi .z code
No smell of fuel
It always starts easy
If I am easy on the throttle I can get it up to 70 but it has no power .
Its not cutting out or stalling.
It ticks over fine and will rev fine when it's not moving.

one of my previous vans was an 87 Safari that did something very similar. Would start and idle, but when trying to go I had to really baby it. Sometimes just putting it in gear it would die. It would always star right back up.

Ended up being the fuel pump.

Be careful if you replace the pump. After I did mine it was fine for a while and then one day on the way home from work it would barely run, really rough and missing, could not get it over 15mph. It turned out that the hose that comes off the fuel pump had split and when the pump pressurized it was just spitting most of the fuel right back into the tank.

Can any one tell me the location of the spark control unit

http://bfy.tw/2Lvo
lol

doyoulikeithere wrote:http://bfy.tw/2Lvo
lol

That is freaking awesome!

Glad you like it.

Found it .

If I set the ignition timing with the bypass wire disconnected to 0° and then reconnect the wire when I recheck the timeing it set to 19° btdc .
Is this correct or is the possible fault

Correct, once you re-connect the wire, the computer takes over.