Buon pomeriggio a tutti ragazzi. Vi seguo da tempo anche se è la prima volta che scrivo. Ho un problema che mi sta mandando al manicomio. Possiedo una fiat coupé 1.8 alla quale è stato eseguito uno swap con motore, cambio, centralina e cablaggio di lancia kappa 20v turbo. La macchina è inoltre decat con scarico ragazzon, pompa benzina walbro 255 l/h, intercooler frontale maggiorato, coreassy rinforzato con 11 pale aspirazione e mappa NOVITEC. La pressione del turbo continua a essere limitata a 1,2 bar ed è sicuramente collegato al parametro FRA -23% presente in diagnosi. Ad oggi posso dirvi che abbiamo escluso sovrappressione benzina nel rail, il regolatore benzina sembra tenere la giusta pressione. Staccando sonda lambda la macchina continua a girare in egual modo. Il tubo di ritorno della benzina sembra libero. Insomma, più che un vero problema di carburazione "grassa/ricca" sembra che la ECU stia solo interpretando che la macchina lo sia. Anche le candele non sono così sporche da giustificare la previsione. Sembra che ci sia un problema di aria calcolata male, ma i valori del debimetro sembrano decenti. Qualcuno ha mai avuto esperienze simili? Mi sareste di enorme aiuto


Good afternoon everyone. I've been following you for a while, even though this is my first post. I'm having a problem that's driving me crazy.

I own a Fiat Coupé 1.8 that had the engine, transmission, ECU, and wiring swapped for a Lancia Kappa 20V turbo. The car is also decatized with a Ragazzon exhaust, a Walbro 255 l/h fuel pump, a larger front intercooler, a reinforced core assembly with 11 intake vanes, and a NOVITEC map. The turbo pressure is still limited to 1.2 bar, which is undoubtedly related to the FRA -23% parameter in the diagnostics.

So far, I can tell you that we've ruled out fuel rail overpressure; the fuel regulator seems to be maintaining the correct pressure. When the lambda sensor is disconnected, the car continues to run the same way. The fuel return line seems loose.

In short, rather than a true "rich/rich" carburetion problem, it seems like the ECU is simply interpreting the car as being "rich." Even the spark plugs aren't dirty enough to warrant the prediction. It seems like there's a problem with miscalculated air, but the flow meter readings seem decent. Has anyone had similar experiences? You'd be a huge help.

Hi there

I am in a similar situation at the moment. After an ECU reset my 20VT ran pretty well, but over a period of about 2-4 weeks of driving, the performance under load/boost becomes sluggish. I don't know if you have actually checked for ECU errors but you're probably getting the same FRA error as I am (I think mine is now at -20.8), in that the short-term fuel trim has maxed out and the ECU has reached its max (lower) limit and cannot remove any more fuel from the mixture - i.e., it thinks she is running rich. However, when I check the live readings at idle for TRA (the long-term fuel trim parameter), it is sitting at +84, meaning the ECU over a longer period of time has been adding fuel to the mix thinking she is running lean.

My theory for this situation is that at idle (when my car runs OK), the mix is indeed running lean (I'll get to why in a minute) so the ECU begins to add fuel to the mixture (TRA). However, under load/acceleration/boost, however, the mixture begins to turn richer so the ECU's reaction to this (FRA) is to remove fuel bit by bit during each period under load/acceleration/boost. I have recently put in a new MAF and Lambda Sensor so I know that the intake and exhaust readings should be OK, and I am not getting any ECU errors pertaining to those sensors (whereas I was before - the SC/OC error).

I have not been able to locate it yet, but I think there must be an air leak somewhere in the system after the MAF. At idle, when the ECU thinks she is running lean, I am thinking that the air leak is a much higher percentage of the total air intake and therefore causes the ECU to experience a lean reading. However, during load/acceleration/boost, when the total volume of air that passes through the MAF is a much higher percentage than the air leaking in post-MAF, this creates the 'rich' reading so the ECU FRA starts to remove fuel again. An air leak post-MAF is the only scenario I can think of that would cause the ECU to think completely difference fuel mix scenarios.

My current issue is that I cannot find the source of the leak, nor verify that this indeed the issue.

Hope the above helps and interested to know if you made any progress resolving your issue?

Buonasera Robski, grazie di questa tua risposta. Ormai non contavo più che qualcuno mi avrebbe risposto. Purtroppo non ho ancora risolto il problema. Oggi stesso con la diagnosi, il parametro FRA è magicamente sceso a -16% rispetto il -22% dell' ultima volta. Abbiamo provato a testare ulteriormente il debimetro con un tester per vedere i valori dei volts con auto in movimento (funziona da circa 1 a 4,7 volt con pedale tutto giù!) pertanto sembra che funzioni decentemente. Continuiamo ad avere sospetto possa essere il sensore IAT2 posto sul collettore aspirazione che magari segna una temperatura aria sbagliata, oppure la lambda ormai datata o sporca di olio. Riguardo la presenza di una perdita tra debimetro e turbo, effettivamente dovrei sigillare meglio un tubo del manicotto nel quale arrivano i vapori dell' olio (ho installato un catch can). Chissà che non ci sia una microperdita lì!! Ti aggiornerò a riguardo. Se hai ulteriori informazioni o esiti saranno decisamente graditi


Good evening, Robski, thanks for your reply. I no longer expected anyone to reply. Unfortunately, I haven't solved the problem yet. Today, with the diagnosis, the FRA parameter magically dropped to -16% compared to -22% the last time. We tried further testing the flow meter with a tester to check the volts with the car moving (it works from about 1 to 4.7 volts with the pedal fully depressed!), so it seems to be working decently. We continue to suspect that the IAT2 sensor on the intake manifold may be indicating the wrong air temperature, or the lambda sensor may be outdated or dirty with oil. Regarding the leak between the flow meter and the turbo, I actually need to better seal a hose where the oil vapors enter (I installed a catch can). Who knows, maybe there's a tiny leak there! I'll keep you updated. Any further information or results would be greatly appreciated.

Ciao Gianluca, mentre scrivo questo risposto senza controllarlo ti lo ho tradotto ancora tuo post utilizzando 'google translate'; spero che qualcuno possa aiutarti