1998 C70 2.0 T5 (B5204T3) – WOT Misfire

Gregory91PL · Post by **Gregory91PL** » 11 Sep 2026, 12:38

Guys, I think I have a lead. I'm not popping the champagne just yet, but it's a start.

I routed the vacuum line directly from the turbo compressor housing to the wastegate, bypassing the TCV. It built around 0.3–0.4 bar. 3rd gear, WOT. The MAF reading maxed out at 408 kg/h at 5000 RPM, but the car kept pulling smoothly without any stuttering or hesitation, even though the MAF hit its ceiling.

What seems crucial is that the injector pulse width dropped from 17 ms down to 11–12 ms.

Here is my takeaway (and my hope):
With lower boost, there was less air, meaning less fuel was required to maintain a rich mixture reading on the O2 sensor. The injection time shortened, and the car stopped stuttering.
With higher boost, more air requires more fuel, and the fuel system starts running out of steam.

So here’s the plan:
Drop in a new fuel pump and get the injectors tested/serviced. After 28 years, it’s worth doing anyway.

What do you guys think of this theory?

Post by **matthew1** » 11 Sep 2026, 12:47

I like the new fuel pump and injector service whatever the case, and the theory is plausible. At this point you're wayy down the decision tree. Often at this decision tree depth, you've got to make tough decisions anyway.

Gregory91PL · Post by **Gregory91PL** » 11 Sep 2026, 13:09

Bosch 0 580 314 067? Would you recommend something else?

Post by **matthew1** » 11 Sep 2026, 13:22

Since your car is stock, yes stick with genuine OEM but see this viewtopic.php?t=92685

Gregory91PL · Post by **Gregory91PL** » 12 Sep 2026, 01:33

Maybe Hitachi 133359 is actually a good choice? It probably looks exactly like the original part 1:1. I'm just not sure if it's trustworthy? I'm not familiar with this brand.

Post by **hausmeister** » 12 Sep 2026, 04:02

Never heard of a hitachi fuel pump, but they do make high quality tools etc. I'd go with the bosch probably, only because I never had any car parts from hitachi.

Gregory91PL · Post by **Gregory91PL** » 12 Sep 2026, 04:30

0 580 454 168 looks quite interesting. Apparently it cross-references with fuel pumps used in the Volvo X70/P80 range.

I haven't found any reliable information on its actual flow rate yet, but the aftermarket replacements for this pump are rated with better flow than the 0 580 453 420.

Judging by the dimensions, it also looks like it should fit the factory fuel pump housing.

The price is pretty good as well.

Post by **hausmeister** » 12 Sep 2026, 06:31

looks like ASTEMO is the automotive part of Hitachi, go for it, why not. Seems they manufacture it themselves, which would be my only concern that its some rebranded crap.

Gregory91PL · Post by **Gregory91PL** » 12 Sep 2026, 12:56

I managed to trace the exact succession history of how Bosch superseded these fuel pump part numbers over the years:

0 580 453 420
0 580 464 138
0 580 453 447
0 580 454 168

It looks like 0 580 454 168 is the current, active Bosch part number for a direct, plug-and-play pump insert with proper flow rates for turbocharged engines without any basket modifications. I just ordered one, so I'll report back with an update once I swap it in.

Post by **matthew1** » 12 Sep 2026, 12:59

^ outstanding. Thanks for this Gregory. Part number sequence is particularly valuable.