'91 200TQ - 'hiccup' when accelerating?

[Bart Oleksy]

LL - NY wrote:
> Is this a stock ECU or 1.8 bar chip?
> 
Ummm... I guess a stock one, as I haven't had that replaced since buying 
the car 4 years ago (or so)...

> LL - NY
> 
> On 3/28/06, *Bart Oleksy* <barto at nerdshack.com 
> <mailto:barto at nerdshack.com>> wrote:
> 
>     This is the long-running saga of my '91 200TQ (10-valve) that's had some
>     hard-starting problems for a long time now...but something new has
>     appeared lately.
> 
>     After replacing my Michelin-man turbo hose (and some other vital part,
>     will confirm that later - oh, TPS!) the car was running better and not
>     stalling at lights (!), but I noticed when accelerating hard, the car
>     would give a very quick 'hiccup' at around the 3000-3500 rpm mark in
>     2nd, 3rd, and I think 4th as well...by 'hiccup' I mean the engine would
>     just cut out for a split second and then continue as normal.
> 
>     It's *possible* it was doing this earlier and I didn't notice, as it's
>     pretty close to where I usually shift to the next gear anyway.
> 
>     Also doesn't seem to do it with a gentler acceleration into that same
>     rpm zone, nor have I managed to get it to do the same hiccup in 1st
>     gear, which I brazenly got up to 5500 rpm with no side effects.
> 
>     Hard starting symptoms: Latest is that when it's been sitting outside
>     overnight (Edmonton, Canada, so freezing to lower) it starts very
>     quickly, but after several hours of sitting in a heated underground
>     garage at work, it can take a LONG time of
>     almost-catching-but-not-quite
>     to get it to finally *start*.  Usually starts up right away within 10-15
>       min. of turning it off as well.
> 
>     Mechanic has replaced a number of things related to the hard starting
>     thing (fuel pump check-valve, throttle position switch, some intake
>     hose
>     that had a small hole in it) with only minor difference, and is now
>     suspecting that the injectors are leaking down.  These were supposed to
>     be *very lightly used* injectors when replaced about a year ago by
>     another shop, so I was hopeful that those wouldn't be the problem.
> 
>     Oh, and fuel pressure as measured "right off the head" stays steady,
>     says the latest mechanic.
> 
>     Any thoughts/suggestions on things to look at for the 'hiccup' thing and
>     hard starting issue?
> 
>     Thanks to all.
> 
>     Bart
>     '98 A6 QA
>     '91 200 TQ
>     '86 CGT
> 
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