1st Gen R53 Cooper S Most liked posts in thread: Morning Hard Starts & Now, 1-3k RPM Hesitation/Yoyo/Hiccup

After taking the car for a spin, here are my observations:
1. Sub 2-3krpm hesitation/yoyo still very evident. It's driveable & bearable but it just isn't normal.
2. After turning the engine off, restarts are never 1 click regardless of engine temp & pump priming. Usually have a few false starts, falls flat & dies. Every successful crank always results in perfect idle though. The new fuel filter seems to have done no improvement here.
3. After idling a lot & observing the different rev ranges & behavior in different gears, OBC MPG just hovers around 10ish???? ECU must be adjusting to fuel starvation symtoms?

In the recent coupla months, the ff maintenance/mods/replacements have been done on car:
1: Oil change w/ OEM filter & Castrol Edge. Never consumes oil between changes.
2. New OEM coolant temp sensor. Had 1 around & also to rule out temp error induced start problems.
3. New belt
4. New battery
5. New strut mounts & reinforcement plates
6. New coolant expansion tank to replace the yellow brown 1.
7. New plugs
8. New wires
9. New fuel filter
10. New ATI damper
11. New passenger inner CV boot
I'm just hoping it's not anywhere near the pump. Too pricey a part in such a short time span! & The filter was such a hassle. I still have to check fuel pressure & have the fuel rail pulse/pressure reg, its o-rings & injector o-rings ready. Will follow what Keith said on the pressure check.
Keep those ideas coming. Most of done items were maintenance necessary so I never looked at them goin to waste.
Help still needed at this point.
Thanks guys!

 

Anyone please point me to where the MAP sensor is & how to clean it? Worth trying? thanks!

 

Ok guys, here's a follow up. With the persistent symptoms, I had to gather enough courage & tools, of course, to get down to fuel rail pressure testing. I was bracing myself for low pressure ( no pun intended, heart & prayers to all of Sandy's victims). Somehow, with all these unrelated issues popping at same time, I'm beginning to think there's some truth to "the Law of Attraction". Unfortunately, I'm attracting all the negatives lately...need to think more of happy motoring than maintenance-needed-next, I guess.
Anyway, here are the results:
1. Key at 0: 0psi
2. Key at 2, pump primes: 22psi then drops back to 0 instantly after pump off
3. Engine on after a few tries: 22psi across any rpm
4. A lot of headscratchin!:confused5::confused5::confused5:

All these & no codes. New rail pulse regulator doesn't hold pressure & 22psi is way low in comparison to Keith's guide. Pump relay was switched w/ headlamp washer one, no effect. The Pump? Uh oh, there's your 'Law of Negative Attraction' proof. That's the 1 I feared most. It's supposedly an R56 thing!:confused5:

I've never felt such a mixed bag of emotions(thrill, anticipation, disappointment, triumph, frustration,relief, fun & scalp itch. In no particular order) dealing w/ a car. Those emotions are usually reserved for WaGs, right?:wink:

Anyway, just sharing my 'fun' troubleshootin' adventure. Of course, your thoughts, inputs are all welcome & will be appreciated!

Oh, by the way, after a day's worth of motorin' struggle dealing w/ hiccups, low end power & constant rev matching, I ended w/ a new issue. Chatter on the passenger side of engine that drowns itself when revving...What the??? Head spins! After gatherin' myself, stethoscoped both sides of the charger 1st. Whew, smooth. RELIEF! Checked the new ATI for wobbling- NONE. Scoped the tensioner, THERE! The strut lost 1 bushing. Ziptied it shut temporarily...SILENCE finally.

Sorry for the long post. Your turn, guys. Thanks!

 

Anyone tried the Walbro uprated pump kit that churns out higher pressure & discharge rate of 255lph? Any good? It's supposed to just fit into the VDO pump we have. It's half the cost of a new pump too. Just haven't seen an R53 how-to on this. Thanks!

 

Process would've been much shorter had I dared dig into the pump w/o waiting for the Walbro kit from the UK. Odd for something US-made to have a kit bundled elsewhere.
No regrets though as the parts I've replaced were all for regular & preventive maintenance anyway.
Good luck w/ you hunt. Hope it'll be just as simple as the hose.

 

Chances are I may be the only one to encounter a torn pump hose in the entire 1st gen population!

 

313k mi!!!! WOW! GRATS! Pressure regulator/anti-backflow should be on the pump side, I believe. The one on the rail serves more like a pulse regulator controlling rail pressure at the same time retaining some for start ups. If search points you to more questions than an answer, check the pump itself. Hope it gets sorted.

 

We're on the same page, Zip. e10 has caused nothing but trouble.