(T) HELP! Cinq Injector Warning Light

Newbie & 1st posting.....
L reg Cinq 899cc, 74k miles & son's 1st car bought 2 wks ago from someone we know with full MOT (car not seller) the mot had an advisory on a bandaged centre section of the exhaust (we knew about this before the guy had it mot'd). The car was previously a good runner but a couple of days
after replacing the exhaust centre section the Injector Warning light came on (and off) a couple of times with a loss of power.

I checked for loose wires / sensor plugs and gave the injector a clean
with some carb cleaner. All was well for a while then it came on again
(and off again). I then noticed a leak on the servo hose so I tightened the Jubille clip which appeared to solve the problem. Took it for a
fairly long run. All seemed well until it came on again tonight (more
on than off now). I removed the air filter housing cover (in case it
was being starved of air) but that didnt help. Also when I apply a
steady throttle the revs go up and down slightly.

Any suggestions? ECU / Fuel Injector / Fuel Pump / Fuel Filter /
Lambda / Cat ....
Can anybody help please - the lad's doing his nut! ..... more info to follow as I've posted this on another discussion forum but still no luck. Can anybody help please?

Lambda would be first point of call. Does it run fine from cold then play up when warm?

Cheers

D

I've got an oscilloscope and the Lambda pulses about 0.1v to 0.8v at about 1hz - engine temperature makes no difference whasoever. I posted more info in the technical section but it appears to have been deleted

Thanks Neil

have now moved my thread to (this) technical section. Will post more details in a few minutes in between popping in and out of my garage!

There's no pattern to the fault - the engine will start & run okay, somtimes the warning light comes on. Sometimes the light comes on when the car is running. When the light comes on the engine looses revs and quickly stalls. Using an oscilloscope, when the engine is normal the Lambda sensor pulses approx 0.1 ~ 0.8v when the warning light is on the sensor reads 0v. The Crank sensor reads -3 to +6v at tickover and increases with more revs. Assuming my DVM is accurate the Coil primaries are a little high at 0.8 & 1.0 ohm respectively, secondaries are about 7000 ohm. I've examined the plugs and they appear to be in good shape but I think a new set may be worth a shot. I managed to pick up a used Lambda sensor & Injector from a local car breakers but that didnt make any difference. Can anybody confirm if the higher values on the coil primaries would have an adverse effect?

I had similar problems with my L reg 899cc Cinq. Every 6 months it needed a map sensor ( £30 from Sutton auto Factors). If you can pick one up from the scrapyard you have been using, they might let you have it for £5.
There is a scrapyard in Bestwood Village, Nottingham that usually has a few Cinqs.

Thanks for the info George. We dont have a Haynes manual - can you tel me where the sensor is located please? - I'll stick my scope on it. Thx too for the scrapyard location we've got a good scrappers in Derby.

As you look at the engine bay there is a vacuum pipe running from the back of the throttle body to a rectangular plastic box/sensor ( 50mm x 25mm x 10mm) which is fixed to a metal plate by 3 nuts. The is also an electrical wire connected to the sensor. They can get contaminated easily if the engine is not spot on. I hope I am not sending you in the wrong direction with the diagnosis - but it does sound similar to my problem. I got rid of my Cinq a few months ago - but still have a Sei.

That'd be my guess, too. Worthwhile trying blowing out the pipe before you pop to the scrappy again.

Started her this morning and the light came on. I removed the MAP and there were no leaks / obstructions in the pipe - gave the MAP nipple a suck refitted it and the car started. I lightly tapped the MAP and the car stalled. Got a MAP from the scrappers and since fitting it the car starts, ticks over & revs normally and the injector light does not come on. I'll try it a few more times, give it a road test and (hopefully) come back to report a successful conclusion.

All seems well since fitting the replacement MAP sensor. No more warning light or stalling. Many thanks to those who contributed.

Glad to hear you got it sorted!