360 B200E runs bad and backfires

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frk
Posts: 3
Joined: 05 Mar 2019 01:00 pm

360 B200E runs bad and backfires

Post by frk » 01 Jul 2020 04:57 pm

Hello, so I have a 360 '90 with a B200E and it seems to have either a fuel or an ignition problem, it starts fine and everything, but when running, it idles like crap and at around 3000rpm it stalls or sputters for a few seconds (the higher the gear the longer it does it, 5th gear it does it for 10 seconds), before 3000rpm and after the stall, it seems to run fine and up to redline, whilest decceleration at around the same rpm, it backfires. Does it in neutral aswell and no matter how much i give it gas (however in neutral, it does it for a split second). So it seems like the more load it's under, the longer it does it. No smoke coming from the exhaust. The previous owner did the head gasket, I have cleaned the intake and MAF, checked for air leaks, replaced the TPS and air filter, spark pluks, cables, rotor and cap, ignition coil, o2 sensor, it has a new fuel pump and filters, injectors. Currently I have checked the fuel pressure regulator, at first the vacuum hose was filled with gasoline, however the regulator seems fine, it appears to have leaked there from the intake manifold side, so i think the cold start injector might be the culprit? I plan on checking it out soon but does anyone here have any theories about what could cause erratic running like this? Also maybe someone could send me a picture of their intake or maybe a diagram to see what vacuum goes where? As I could imagine one of the previous owners might have messed up the lines and connected them incorrectly. Thank you ahead.

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TasMan
Posts: 82
Joined: 04 Jun 2019 06:09 pm
Location: Ayr, SW Scotland

Re: 360 B200E runs bad and backfires

Post by TasMan » 01 Jul 2020 05:58 pm

As I was reading your post I immediately thought of the fuel pressure regulator, and then you mentioned fuel in the vacuum line.

I had similar bad running and poor starting after a run (say 15 - 30 mins after stopping, restarting would take a bit of turning over). The car also shuddered around 2500 - 3000 rpm on light load, not backfiring but certainly not happy.

I checked the vacuum line on the regulator and had fuel present. Unlikely fuel is coming up from the intake as it is under negative pressure so I would recommend changing out the regulator. There are regulators on Ebay for around £30, non-original but perfectly fine. I changed the regulator on my car and the difference is night and day. The old one had a leak between the vacuum side and the fuel side, modern fuels probably taken their toll on the internals.

Worth noting the cold start injector on my car has been disconnected, was like that when I got it, I will re-instate it in due course and see how it goes. Still starts and runs fine....

I don't think you have mentioned changing the crankshaft renix timing sensor ? I changed mine out, while the old one was just about within the spec tolerance the new one was bang on, again relatively cheap and easy to do.

Regards Dave
1987 360 GLT

frk
Posts: 3
Joined: 05 Mar 2019 01:00 pm

Re: 360 B200E runs bad and backfires

Post by frk » 01 Jul 2020 07:07 pm

Thank you for your reply Dave, i will change my fuel pressure regulator in the next few days and keep you posted, would a 700 series one do the trick? You are right, I have yet to change my timing sensor, the previous owner said he had done it, when he got the car, but it does look worn, i will certainly look into replacing it, better safe than sorry :)

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TasMan
Posts: 82
Joined: 04 Jun 2019 06:09 pm
Location: Ayr, SW Scotland

Re: 360 B200E runs bad and backfires

Post by TasMan » 01 Jul 2020 08:41 pm

Sorry I can't advise on whether a 700 series regulator is the same.
Checking Ebay just now there are brand new Lucas and SMPE regulators available for around £28, a good price I would say. I have to pass on credit to others on here who put me onto the fuel pressure regulator, now I am just passing on my positive experience :)

The crank sensor can be checked with a multimeter, think it is around 220 ohms but Haynes or the Green Books on here will confirm. Mine was just on tolerance but I figured it better to renew given age etc, the old one didn't look great when removed. Fairly cheap to source and another thing to eliminate.

Keep us posted on how you get on!
Cheers Dave
1987 360 GLT

frk
Posts: 3
Joined: 05 Mar 2019 01:00 pm

Re: 360 B200E runs bad and backfires

Post by frk » 03 Jul 2020 02:04 pm

So i replaced the fuel rail and the regulator but to no avail, still the same old, also tried blocking off the fuel going to the cold start injetor but no difference, so its unlikely to be the cold start injector or anything in the fuel system as i have replaced the whole nine.

Next step is checking the crank position sensor and probably replacing that as well just to remove that from the list.

Ride_on
Posts: 2255
Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: 360 B200E runs bad and backfires

Post by Ride_on » 03 Jul 2020 10:39 pm

frk wrote:
01 Jul 2020 04:57 pm
o2 sensor
B200E's don't have O2 sensors, are your sure its not a B200F?
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

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