P1128 and P1130 - Fuel pump issues maybe? UPDATE AND EASY FIX

My car is throwing up two codes P1128 and P1130 oxygen sensing adaptation idle range bank 1 and 2. Runs fine but when hot it can sometimes take a while to start, needs to be cranked 8 or 9 times, then it will run fine, idle can be a bit eractic too. Had a new MAF and other bits done on the car over the last year or so, this is a new problem and has been diagnosed as a potential fuel pump issue so it’s booked in for March. However I have a potential road trip first week of March so am thinking I might have a go myself, it’s a 1999 C4. A couple of questions, does the fuel pump seem likely? If the consensus is yea has anyone changed one is it an ok job to do at home? I have tools and a garage and am quite handy. Is Design 911 and OPC best places to source pump?

Fuel pump went on mine last year with no warning it just started running sporadically. The cost of the replacement is expensive but no way around it unfortunately and I paid to get it switched out. I think from memory the design 911 pump would be the same as one from your opc Tbh I’m not 100% sure your symptoms would be the pump but it could be the early stages of it going

I started getting occasional idle range o2 adaption codes on my Turbo, it turned out to be the maf. Do you know anyone with the same engine who's maf you can try, I know yours has been replaced recently, but doesn't mean it can't be that. You could also buy a fuel pressure tester from Ebay, they're only cheap!

Quotes source post: 2785848

Are they easy to use? This could be a good call

Quotes source post: 2785848

I could try cleaning my MAF, I have MAF cleaner, I know someone with a C4 996.2 is that the same as the 996.1?

Quick update, I removed the MAF and air box to give me access to the throttle body. I cleaned the MAF with specific MAF cleaner, looked a little dirty, sprayed it off and let it dry. I also checked the TB for oil as the AOS as this could also cause issues. The TB was a bit dirty but not oily, so I think the AOS is ok. Put it all back together and did the reset with the ignition - leave on second click for 60s switch off for 10s then started it. It initially felt rough and lumpy, took it for a 30 min blast and all seems good, no hot start issue and.no codes on my reader. Fingers crossed I may have just saved myself £800

UPDATE Things are never that simple in Porsche World, it seems cleaning the MAF hasn’t made a difference, luckily I never cancelled my appointment at my Indie for replacement fuel pump. I’m not 100% convinced it is that, as this is an expensive swap, circa £750 for replacement, should the garage do a pressure test? To diagnose a week pump?

A pressure test is definitely required to check a failing fuel pump. You should be able to test it with the FPR vacuum line plugged in and with it removed (ie. without vacuum which is Wide Open Throttle). These value are easy to find online. It's an hour's job to change it, super easy (especially with a 90% empty tank!). I think ERA is the OE supplier? £280 on autodoc right now so £750 for the job seems juicy to me but if it includes diagnosis too... o2 readings could be the 02 sensors? definitely check the fuel pressures as step 1.

Thanks for the reply, it had new oxygen sensor fitted last year, so pretty sure that’s not it.

If it does turn out the be a fuel pump, VDO is the OE supplier to Porsche. Early models are VDO E22-041-087Z (996 620 102 00), later models are VDO A2C52124455Z (996 620 132 00). The split is between 2001 and 2002 model years so part way through 996.1 production when the minor interior face lift was done.

Evening, the car is a 1999 C4, can you contact VDO directly? It’s going to have some further checks before I debt the pump done, sohepefully I can eliminate every tease first.

Could be a lambda sensor playing up, are they the original ones still?

As you are getting the codes for both sides of the engine(lean mixture) that says to me it's something that's common to both sides, the usual suspects, maf, low fuel pressure, air leak on induction side. A good indy should be able to check the maf voltage, both with engine stopped should be 1.0 volts, and at warm tickover around 1.2 volts. They should also be able to measure the fuel pressure. Should be 3.8bar with engine stopped but with the fuel pump running via tester, and around 3.2-3.3 bar with the engine running. The could also do a smoke test on the inlet manifold. Also check the exhaust for leaks although less likely as would normally only affect one side! They should be doing diagnostics before changing expensive parts

Thanks guys all good advise, I’m going to a different indie to see if they can diagnose, I will put the above list together for suggestions for diagnostics

Booked in for the 19th, let’s see what they diagnose, if it is the fuel pump, I’m going to have a go at fitting myself, so I might be calling on the collective for some advise and youtube links to help me feck it up, then I’ll pay my Indie to rectify my ***** up and charge me twice as much