Engine bogs down

bratty61
0

Asked by Aug 15, 2010 at 10:12 AM about the 1997 Subaru Legacy

Question type: Maintenance & Repair

I have a 97 Legacy, when friving the car after 3 or 4 miles, the engine bogs down, like one that has restricted exhaust. Mechanic has checked the back pressure, 1.2psi@2500rpm.Fuel pressure 28psiKoer volume 1pt in 10 seconds. When engine runs normally, fuel injector pulse width is 3ms @idle in park. Wehn engine bogs down, fuel injector pulse width on #1 & #2 injuctors is .5ms and #3  is 3ms @ idle. o2 sensor voltage is 0 Fuel pressure and volume are still ok. No change in any other sensor voltage while engine is bogging down. No engine DTC's stored.

2 Answers

Nick Eidemiller
5,445

a couple things come to mind, have you replaced all the filters yet (air, fuel, etc.)? another possibility is that the rings on your pistons or even just 1 piston are bad causing bad compression, the last thing that pops into my mind is that the rod bearings could be sticking from lack of lubrication caused by a bad oiling system or sludge in your oil. Now I don't know what all test have been run for sure because I don't know how you can simulate the conditions of driving with a load on the motor whil runing tests upon these systems you listed but I hope this helps.

Brandon McMillan
75

Where are you reading fuel pressure at? Hopefully at the rails. Still sounds like a fuel filter is most likely culprit, or some other problem with the fuel system. Hell, I've had the exact same symptoms from getting bad gas, which is happening a lot more often nowadays. May even be an injector issue and sure you can check pulse width but thats just the electrical input, one may still be sticking or something. I would make sure fuel delivery is on par and find a way to test Air/Fuel ratio, find a quickie wideband tester or something :). Gotta remember, it IS a 12 year old car.

Your Answer

Add photo

Related Questions

Search Subaru Legacy Questions

Subaru Legacy Experts

#1 Anthony_60
Anthony_60
Reputation 900
#2 Nick Eidemiller
Nick Eidemiller
Reputation 660
#3 dandyoun
dandyoun
Reputation 570
View All

Related Models For Sale

Used Subaru Impreza"
210 Great Deals out of 10,736 listings starting at $1,800
Used Subaru Forester"
322 Great Deals out of 20,837 listings starting at $1,199
Used Honda Accord"
1,128 Great Deals out of 73,138 listings starting at $1,400
Used Toyota Camry"
1,539 Great Deals out of 88,199 listings starting at $695
Used Honda Civic"
857 Great Deals out of 53,056 listings starting at $995
Used BMW 3 Series"
1,214 Great Deals out of 38,443 listings starting at $1,450
Used Toyota Corolla"
1,143 Great Deals out of 66,650 listings starting at $1,295
Used Nissan Altima"
1,425 Great Deals out of 85,649 listings starting at $999
Used Audi A4"
268 Great Deals out of 12,338 listings starting at $1,299

Used Cars For Sale

2017 Subaru Legacy For Sale
6,716 listings starting at $20,165
2016 Subaru Legacy For Sale
22 Great Deals out of 1,867 listings starting at $17,912
2015 Subaru Legacy For Sale
50 Great Deals out of 836 listings starting at $14,900
2014 Subaru Legacy For Sale
43 Great Deals out of 1,148 listings starting at $9,799
2013 Subaru Legacy For Sale
55 Great Deals out of 1,066 listings starting at $9,495