Bo-Ty

We are troubleshooting an acceleration problem. when accelerator is pressed engine fails to respond until several seconds pass. Eventually power climbs to meet demand from accelerator. Check engine light comes on..codes read multiple cylinder misfire..also get "fuel system1 CL Fault" on our code reader. New plugs installed and tried replacing coil units. Problem remains.. First .. What does OL and CL mean on the Fuel Sytem1 line on the code reader and should we focus on fuel delivery system? Or HELP!

ezone

OL and CL are "open loop" and "closed loop".

Got actual code numbers?
Got freeze frame data?
Got any live engine data?
Got fuel pressure readings at the time if no power? And is the fuel actually good uncontaminated gasoline?

Is there a bug or something stuck in the MAF sensor?

Bo-Ty

We will check the MAF sensor..Thanks. Our code reader doesnt offer actual fuel press numbers, just says "fault". We are still learning how to understand the data we get from our code reader. It can read live data except still provides no fuel pressure numbers.. unless I'm not finding the right parameter to view. Unclear how to interpret Freeze Frame data..Thank you for any insight you might have to offer.

ezone

The only way to read fuel pressure is with a real gauge. There is no data for it on these cars.
But don't go there yet.

Post your actual code numbers.
Post your freeze frame data if you have it.

Freeze frame: It's a snapshot of some data items captured at the moment the PCM set a code, and there should be the associated code number that goes with the data (helpful if there are multiple codes).
It allows us to see some conditions like engine temperature, vehicle speed, fuel trims, RPM, throttle position, etc. when the code set.

Bo-Ty

We cleaned the MAF sensor. wasnt dirty and no change to engine performance, in fact it now fails to accelerate well all the time. We are trying to get the saved data into this pc to share. its a Cen-Tec 98614 from harbor freight..doesnt that say it all? 3 logged codes as follows 1. cylinder 3 misfire detected, 2. cylinder 4 misfire detected, and 3. multiple cylinder misfire detected. Along with "Fuelsys1 OL-fault" reading ..thoughts?

Bo-Ty

DTC_CNT 3
FUELSYS1 OL_Fault
FUELSYS2 N/A
LOAD_PCT(%) 65.5
ETC(°C) 85
SHRTFT1(%) 0.0
LONGFT1(%) 0.0
MAP(kPa) 36
RPM(/min) 3694
VSS(km/h) 65
SPARKADV(°) 38
IAT(°C) 25
MAF(g/s) 18.41
TP(%) 21.2
O2S B1S12--B2S----
O2B1S2(V) 0.000
SHRTFTB1S2(%) 0.0
OBD OBD2
RUNTM(sec) 325
MIL_DIST(km) 4
EGR_PTC(%) 0.0
EGR_ERR(%) 0.0
EVAP_PCT(%) 0.0
FLI(%) 38.8
WARM_UPS 1
CLR_DIST(km) 8
EVAP_VP(Pa) 26.50
BARO(kPa) 100
EQ_RAT11 1.979
O2S11(mA) -0.578
CATEMP11(°C)750.50
VPWR(V) 14.525
LOAD_ABS(%) 29.8
EQ_RAT 1.999
TP_R(%) 12.9
TP_B(%) 37.3
APP_D(%) 30.2
APP_E(%) 15.3
TAC_PCT(%) 11.4
------------------
Here is a capture of running live data on most recent test run following MAF cleaning.

Bo-Ty

Pending Codes
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0300 Random / Multiple Cylinder Misfire Detected
From saved freeze frame

ezone

Ok I now understand where you got the OL-fault from... I thought there was some code found that was described as such.

I think that in the condition you captured your data in, it is either in open loop due to the rate of acceleration or because of fault codes....It's hard to tell from where I sit.

Do you have the freeze frame data to post? It will be a list similar to your above capture.

So you have misfire codes. (I thought there would be a fuel related code based on what you said in the first post.)

Can you feel misfire?
Does it miss at idle?
Does it miss only during acceleration?
Does it miss only at higher RPM?
Is the miss dependent on acceleration load?

How many miles on the car?
Any other recent work?
Any other known issues?

Compression, spark, and fuel. Which one of these goes wrong at the time of poor running?


It's real tough to just tell someone to toss a certain part, there are waaaaay too many possible causes of misfire codes.